From 8b23f6236cd51daab47844fa8b8dde25c0a36021 Mon Sep 17 00:00:00 2001
From: Libin YANG <contact@yanglibin.info>
Date: Sat, 6 Dec 2025 07:59:58 +0800
Subject: [PATCH] feat: add ts solution to lc problem: No.3578

---
 .../README.md                                 | 651 +-----------------
 .../README_EN.md                              | 651 +-----------------
 .../Solution.ts                               | 651 +-----------------
 3 files changed, 87 insertions(+), 1866 deletions(-)

diff --git a/solution/3500-3599/3578.Count Partitions With Max-Min Difference at Most K/README.md b/solution/3500-3599/3578.Count Partitions With Max-Min Difference at Most K/README.md
index eb049df8701e1..1f776a86767c9 100644
--- a/solution/3500-3599/3578.Count Partitions With Max-Min Difference at Most K/README.md	
+++ b/solution/3500-3599/3578.Count Partitions With Max-Min Difference at Most K/README.md	
@@ -216,643 +216,50 @@ func countPartitions(nums []int, k int) int {
 #### TypeScript
 
 ```ts
+import { AvlTree } from 'datastructures-js';
+
 function countPartitions(nums: number[], k: number): number {
-    const mod = 10 ** 9 + 7;
+    const mod = 1_000_000_007;
     const n = nums.length;
-    const sl = new TreapMultiSet<number>((a, b) => a - b);
-    const f: number[] = Array(n + 1).fill(0);
-    const g: number[] = Array(n + 1).fill(0);
-    f[0] = 1;
-    g[0] = 1;
-    for (let l = 1, r = 1; r <= n; ++r) {
-        const x = nums[r - 1];
-        sl.add(x);
-        while (sl.last()! - sl.first()! > k) {
-            sl.delete(nums[l - 1]);
-            l++;
-        }
-        f[r] = (g[r - 1] - (l >= 2 ? g[l - 2] : 0) + mod) % mod;
-        g[r] = (g[r - 1] + f[r]) % mod;
-    }
-    return f[n];
-}
-
-type CompareFunction<T, R extends 'number' | 'boolean'> = (
-    a: T,
-    b: T,
-) => R extends 'number' ? number : boolean;
-
-interface ITreapMultiSet<T> extends Iterable<T> {
-    add: (...value: T[]) => this;
-    has: (value: T) => boolean;
-    delete: (value: T) => void;
-
-    bisectLeft: (value: T) => number;
-    bisectRight: (value: T) => number;
-
-    indexOf: (value: T) => number;
-    lastIndexOf: (value: T) => number;
-
-    at: (index: number) => T | undefined;
-    first: () => T | undefined;
-    last: () => T | undefined;
-
-    lower: (value: T) => T | undefined;
-    higher: (value: T) => T | undefined;
-    floor: (value: T) => T | undefined;
-    ceil: (value: T) => T | undefined;
-
-    shift: () => T | undefined;
-    pop: (index?: number) => T | undefined;
-
-    count: (value: T) => number;
-
-    keys: () => IterableIterator<T>;
-    values: () => IterableIterator<T>;
-    rvalues: () => IterableIterator<T>;
-    entries: () => IterableIterator<[number, T]>;
-
-    readonly size: number;
-}
-
-class TreapNode<T = number> {
-    value: T;
-    count: number;
-    size: number;
-    priority: number;
-    left: TreapNode<T> | null;
-    right: TreapNode<T> | null;
-
-    constructor(value: T) {
-        this.value = value;
-        this.count = 1;
-        this.size = 1;
-        this.priority = Math.random();
-        this.left = null;
-        this.right = null;
-    }
-
-    static getSize(node: TreapNode<any> | null): number {
-        return node?.size ?? 0;
-    }
-
-    static getFac(node: TreapNode<any> | null): number {
-        return node?.priority ?? 0;
-    }
-
-    pushUp(): void {
-        let tmp = this.count;
-        tmp += TreapNode.getSize(this.left);
-        tmp += TreapNode.getSize(this.right);
-        this.size = tmp;
-    }
-
-    rotateRight(): TreapNode<T> {
-        // eslint-disable-next-line @typescript-eslint/no-this-alias
-        let node: TreapNode<T> = this;
-        const left = node.left;
-        node.left = left?.right ?? null;
-        left && (left.right = node);
-        left && (node = left);
-        node.right?.pushUp();
-        node.pushUp();
-        return node;
-    }
-
-    rotateLeft(): TreapNode<T> {
-        // eslint-disable-next-line @typescript-eslint/no-this-alias
-        let node: TreapNode<T> = this;
-        const right = node.right;
-        node.right = right?.left ?? null;
-        right && (right.left = node);
-        right && (node = right);
-        node.left?.pushUp();
-        node.pushUp();
-        return node;
-    }
-}
-
-class TreapMultiSet<T = number> implements ITreapMultiSet<T> {
-    private readonly root: TreapNode<T>;
-    private readonly compareFn: CompareFunction<T, 'number'>;
-    private readonly leftBound: T;
-    private readonly rightBound: T;
-
-    constructor(compareFn?: CompareFunction<T, 'number'>);
-    constructor(compareFn: CompareFunction<T, 'number'>, leftBound: T, rightBound: T);
-    constructor(
-        compareFn: CompareFunction<T, any> = (a: any, b: any) => a - b,
-        leftBound: any = -Infinity,
-        rightBound: any = Infinity,
-    ) {
-        this.root = new TreapNode<T>(rightBound);
-        this.root.priority = Infinity;
-        this.root.left = new TreapNode<T>(leftBound);
-        this.root.left.priority = -Infinity;
-        this.root.pushUp();
-
-        this.leftBound = leftBound;
-        this.rightBound = rightBound;
-        this.compareFn = compareFn;
-    }
-
-    get size(): number {
-        return this.root.size - 2;
-    }
-
-    get height(): number {
-        const getHeight = (node: TreapNode<T> | null): number => {
-            if (node == null) return 0;
-            return 1 + Math.max(getHeight(node.left), getHeight(node.right));
-        };
-
-        return getHeight(this.root);
-    }
-
-    /**
-     *
-     * @complexity `O(logn)`
-     * @description Returns true if value is a member.
-     */
-    has(value: T): boolean {
-        const compare = this.compareFn;
-        const dfs = (node: TreapNode<T> | null, value: T): boolean => {
-            if (node == null) return false;
-            if (compare(node.value, value) === 0) return true;
-            if (compare(node.value, value) < 0) return dfs(node.right, value);
-            return dfs(node.left, value);
-        };
-
-        return dfs(this.root, value);
-    }
-
-    /**
-     *
-     * @complexity `O(logn)`
-     * @description Add value to sorted set.
-     */
-    add(...values: T[]): this {
-        const compare = this.compareFn;
-        const dfs = (
-            node: TreapNode<T> | null,
-            value: T,
-            parent: TreapNode<T>,
-            direction: 'left' | 'right',
-        ): void => {
-            if (node == null) return;
-            if (compare(node.value, value) === 0) {
-                node.count++;
-                node.pushUp();
-            } else if (compare(node.value, value) > 0) {
-                if (node.left) {
-                    dfs(node.left, value, node, 'left');
-                } else {
-                    node.left = new TreapNode(value);
-                    node.pushUp();
-                }
-
-                if (TreapNode.getFac(node.left) > node.priority) {
-                    parent[direction] = node.rotateRight();
-                }
-            } else if (compare(node.value, value) < 0) {
-                if (node.right) {
-                    dfs(node.right, value, node, 'right');
-                } else {
-                    node.right = new TreapNode(value);
-                    node.pushUp();
-                }
-
-                if (TreapNode.getFac(node.right) > node.priority) {
-                    parent[direction] = node.rotateLeft();
-                }
-            }
-            parent.pushUp();
-        };
-
-        values.forEach(value => dfs(this.root.left, value, this.root, 'left'));
-        return this;
-    }
-
-    /**
-     *
-     * @complexity `O(logn)`
-     * @description Remove value from sorted set if it is a member.
-     * If value is not a member, do nothing.
-     */
-    delete(value: T): void {
-        const compare = this.compareFn;
-        const dfs = (
-            node: TreapNode<T> | null,
-            value: T,
-            parent: TreapNode<T>,
-            direction: 'left' | 'right',
-        ): void => {
-            if (node == null) return;
-
-            if (compare(node.value, value) === 0) {
-                if (node.count > 1) {
-                    node.count--;
-                    node?.pushUp();
-                } else if (node.left == null && node.right == null) {
-                    parent[direction] = null;
-                } else {
-                    // 旋到根节点
-                    if (
-                        node.right == null ||
-                        TreapNode.getFac(node.left) > TreapNode.getFac(node.right)
-                    ) {
-                        parent[direction] = node.rotateRight();
-                        dfs(parent[direction]?.right ?? null, value, parent[direction]!, 'right');
-                    } else {
-                        parent[direction] = node.rotateLeft();
-                        dfs(parent[direction]?.left ?? null, value, parent[direction]!, 'left');
-                    }
-                }
-            } else if (compare(node.value, value) > 0) {
-                dfs(node.left, value, node, 'left');
-            } else if (compare(node.value, value) < 0) {
-                dfs(node.right, value, node, 'right');
-            }
-
-            parent?.pushUp();
-        };
-
-        dfs(this.root.left, value, this.root, 'left');
-    }
-
-    /**
-     *
-     * @complexity `O(logn)`
-     * @description Returns an index to insert value in the sorted set.
-     * If the value is already present, the insertion point will be before (to the left of) any existing values.
-     */
-    bisectLeft(value: T): number {
-        const compare = this.compareFn;
-        const dfs = (node: TreapNode<T> | null, value: T): number => {
-            if (node == null) return 0;
-
-            if (compare(node.value, value) === 0) {
-                return TreapNode.getSize(node.left);
-            } else if (compare(node.value, value) > 0) {
-                return dfs(node.left, value);
-            } else if (compare(node.value, value) < 0) {
-                return dfs(node.right, value) + TreapNode.getSize(node.left) + node.count;
-            }
 
-            return 0;
-        };
+    const cnt = new Map<number, number>();
+    const st = new AvlTree<number>((a, b) => a - b);
 
-        return dfs(this.root, value) - 1;
-    }
-
-    /**
-     *
-     * @complexity `O(logn)`
-     * @description Returns an index to insert value in the sorted set.
-     * If the value is already present, the insertion point will be before (to the right of) any existing values.
-     */
-    bisectRight(value: T): number {
-        const compare = this.compareFn;
-        const dfs = (node: TreapNode<T> | null, value: T): number => {
-            if (node == null) return 0;
-
-            if (compare(node.value, value) === 0) {
-                return TreapNode.getSize(node.left) + node.count;
-            } else if (compare(node.value, value) > 0) {
-                return dfs(node.left, value);
-            } else if (compare(node.value, value) < 0) {
-                return dfs(node.right, value) + TreapNode.getSize(node.left) + node.count;
-            }
-
-            return 0;
-        };
-        return dfs(this.root, value) - 1;
-    }
-
-    /**
-     *
-     * @complexity `O(logn)`
-     * @description Returns the index of the first occurrence of a value in the set, or -1 if it is not present.
-     */
-    indexOf(value: T): number {
-        const compare = this.compareFn;
-        let isExist = false;
-
-        const dfs = (node: TreapNode<T> | null, value: T): number => {
-            if (node == null) return 0;
-
-            if (compare(node.value, value) === 0) {
-                isExist = true;
-                return TreapNode.getSize(node.left);
-            } else if (compare(node.value, value) > 0) {
-                return dfs(node.left, value);
-            } else if (compare(node.value, value) < 0) {
-                return dfs(node.right, value) + TreapNode.getSize(node.left) + node.count;
-            }
-
-            return 0;
-        };
-        const res = dfs(this.root, value) - 1;
-        return isExist ? res : -1;
-    }
-
-    /**
-     *
-     * @complexity `O(logn)`
-     * @description Returns the index of the last occurrence of a value in the set, or -1 if it is not present.
-     */
-    lastIndexOf(value: T): number {
-        const compare = this.compareFn;
-        let isExist = false;
-
-        const dfs = (node: TreapNode<T> | null, value: T): number => {
-            if (node == null) return 0;
-
-            if (compare(node.value, value) === 0) {
-                isExist = true;
-                return TreapNode.getSize(node.left) + node.count - 1;
-            } else if (compare(node.value, value) > 0) {
-                return dfs(node.left, value);
-            } else if (compare(node.value, value) < 0) {
-                return dfs(node.right, value) + TreapNode.getSize(node.left) + node.count;
-            }
-
-            return 0;
-        };
-
-        const res = dfs(this.root, value) - 1;
-        return isExist ? res : -1;
-    }
-
-    /**
-     *
-     * @complexity `O(logn)`
-     * @description Returns the item located at the specified index.
-     * @param index The zero-based index of the desired code unit. A negative index will count back from the last item.
-     */
-    at(index: number): T | undefined {
-        if (index < 0) index += this.size;
-        if (index < 0 || index >= this.size) return undefined;
-
-        const dfs = (node: TreapNode<T> | null, rank: number): T | undefined => {
-            if (node == null) return undefined;
-
-            if (TreapNode.getSize(node.left) >= rank) {
-                return dfs(node.left, rank);
-            } else if (TreapNode.getSize(node.left) + node.count >= rank) {
-                return node.value;
-            } else {
-                return dfs(node.right, rank - TreapNode.getSize(node.left) - node.count);
-            }
-        };
-
-        const res = dfs(this.root, index + 2);
-        return ([this.leftBound, this.rightBound] as any[]).includes(res) ? undefined : res;
-    }
-
-    /**
-     *
-     * @complexity `O(logn)`
-     * @description Find and return the element less than `val`, return `undefined` if no such element found.
-     */
-    lower(value: T): T | undefined {
-        const compare = this.compareFn;
-        const dfs = (node: TreapNode<T> | null, value: T): T | undefined => {
-            if (node == null) return undefined;
-            if (compare(node.value, value) >= 0) return dfs(node.left, value);
-
-            const tmp = dfs(node.right, value);
-            if (tmp == null || compare(node.value, tmp) > 0) {
-                return node.value;
-            } else {
-                return tmp;
-            }
-        };
-
-        const res = dfs(this.root, value) as any;
-        return res === this.leftBound ? undefined : res;
-    }
-
-    /**
-     *
-     * @complexity `O(logn)`
-     * @description Find and return the element greater than `val`, return `undefined` if no such element found.
-     */
-    higher(value: T): T | undefined {
-        const compare = this.compareFn;
-        const dfs = (node: TreapNode<T> | null, value: T): T | undefined => {
-            if (node == null) return undefined;
-            if (compare(node.value, value) <= 0) return dfs(node.right, value);
-
-            const tmp = dfs(node.left, value);
-
-            if (tmp == null || compare(node.value, tmp) < 0) {
-                return node.value;
-            } else {
-                return tmp;
-            }
-        };
-
-        const res = dfs(this.root, value) as any;
-        return res === this.rightBound ? undefined : res;
-    }
-
-    /**
-     *
-     * @complexity `O(logn)`
-     * @description Find and return the element less than or equal to `val`, return `undefined` if no such element found.
-     */
-    floor(value: T): T | undefined {
-        const compare = this.compareFn;
-        const dfs = (node: TreapNode<T> | null, value: T): T | undefined => {
-            if (node == null) return undefined;
-            if (compare(node.value, value) === 0) return node.value;
-            if (compare(node.value, value) >= 0) return dfs(node.left, value);
-
-            const tmp = dfs(node.right, value);
-            if (tmp == null || compare(node.value, tmp) > 0) {
-                return node.value;
-            } else {
-                return tmp;
-            }
-        };
-
-        const res = dfs(this.root, value) as any;
-        return res === this.leftBound ? undefined : res;
-    }
-
-    /**
-     *
-     * @complexity `O(logn)`
-     * @description Find and return the element greater than or equal to `val`, return `undefined` if no such element found.
-     */
-    ceil(value: T): T | undefined {
-        const compare = this.compareFn;
-        const dfs = (node: TreapNode<T> | null, value: T): T | undefined => {
-            if (node == null) return undefined;
-            if (compare(node.value, value) === 0) return node.value;
-            if (compare(node.value, value) <= 0) return dfs(node.right, value);
-
-            const tmp = dfs(node.left, value);
-
-            if (tmp == null || compare(node.value, tmp) < 0) {
-                return node.value;
-            } else {
-                return tmp;
-            }
-        };
-
-        const res = dfs(this.root, value) as any;
-        return res === this.rightBound ? undefined : res;
-    }
-
-    /**
-     * @complexity `O(logn)`
-     * @description
-     * Returns the last element from set.
-     * If the set is empty, undefined is returned.
-     */
-    first(): T | undefined {
-        const iter = this.inOrder();
-        iter.next();
-        const res = iter.next().value;
-        return res === this.rightBound ? undefined : res;
-    }
-
-    /**
-     * @complexity `O(logn)`
-     * @description
-     * Returns the last element from set.
-     * If the set is empty, undefined is returned .
-     */
-    last(): T | undefined {
-        const iter = this.reverseInOrder();
-        iter.next();
-        const res = iter.next().value;
-        return res === this.leftBound ? undefined : res;
-    }
-
-    /**
-     * @complexity `O(logn)`
-     * @description
-     * Removes the first element from an set and returns it.
-     * If the set is empty, undefined is returned and the set is not modified.
-     */
-    shift(): T | undefined {
-        const first = this.first();
-        if (first === undefined) return undefined;
-        this.delete(first);
-        return first;
-    }
-
-    /**
-     * @complexity `O(logn)`
-     * @description
-     * Removes the last element from an set and returns it.
-     * If the set is empty, undefined is returned and the set is not modified.
-     */
-    pop(index?: number): T | undefined {
-        if (index == null) {
-            const last = this.last();
-            if (last === undefined) return undefined;
-            this.delete(last);
-            return last;
+    function insert(x: number) {
+        const c = (cnt.get(x) || 0) + 1;
+        cnt.set(x, c);
+        if (c === 1) {
+            st.insert(x);
         }
-
-        const toDelete = this.at(index);
-        if (toDelete == null) return;
-        this.delete(toDelete);
-        return toDelete;
-    }
-
-    /**
-     *
-     * @complexity `O(logn)`
-     * @description
-     * Returns number of occurrences of value in the sorted set.
-     */
-    count(value: T): number {
-        const compare = this.compareFn;
-        const dfs = (node: TreapNode<T> | null, value: T): number => {
-            if (node == null) return 0;
-            if (compare(node.value, value) === 0) return node.count;
-            if (compare(node.value, value) < 0) return dfs(node.right, value);
-            return dfs(node.left, value);
-        };
-
-        return dfs(this.root, value);
-    }
-
-    *[Symbol.iterator](): Generator<T, any, any> {
-        yield* this.values();
-    }
-
-    /**
-     * @description
-     * Returns an iterable of keys in the set.
-     */
-    *keys(): Generator<T, any, any> {
-        yield* this.values();
     }
 
-    /**
-     * @description
-     * Returns an iterable of values in the set.
-     */
-    *values(): Generator<T, any, any> {
-        const iter = this.inOrder();
-        iter.next();
-        const steps = this.size;
-        for (let _ = 0; _ < steps; _++) {
-            yield iter.next().value;
+    function erase(x: number) {
+        const c = cnt.get(x)! - 1;
+        cnt.set(x, c);
+        if (c === 0) {
+            st.remove(x);
         }
     }
 
-    /**
-     * @description
-     * Returns a generator for reversed order traversing the set.
-     */
-    *rvalues(): Generator<T, any, any> {
-        const iter = this.reverseInOrder();
-        iter.next();
-        const steps = this.size;
-        for (let _ = 0; _ < steps; _++) {
-            yield iter.next().value;
-        }
-    }
+    const f = Array(n + 1).fill(0);
+    const g = Array(n + 1).fill(0);
+    f[0] = 1;
+    g[0] = 1;
 
-    /**
-     * @description
-     * Returns an iterable of key, value pairs for every entry in the set.
-     */
-    *entries(): IterableIterator<[number, T]> {
-        const iter = this.inOrder();
-        iter.next();
-        const steps = this.size;
-        for (let i = 0; i < steps; i++) {
-            yield [i, iter.next().value];
-        }
-    }
+    for (let l = 1, r = 1; r <= n; ++r) {
+        const x = nums[r - 1];
+        insert(x);
 
-    private *inOrder(root: TreapNode<T> | null = this.root): Generator<T, any, any> {
-        if (root == null) return;
-        yield* this.inOrder(root.left);
-        const count = root.count;
-        for (let _ = 0; _ < count; _++) {
-            yield root.value;
+        while (st.max()!.getValue() - st.min()!.getValue() > k) {
+            erase(nums[l - 1]);
+            l++;
         }
-        yield* this.inOrder(root.right);
-    }
 
-    private *reverseInOrder(root: TreapNode<T> | null = this.root): Generator<T, any, any> {
-        if (root == null) return;
-        yield* this.reverseInOrder(root.right);
-        const count = root.count;
-        for (let _ = 0; _ < count; _++) {
-            yield root.value;
-        }
-        yield* this.reverseInOrder(root.left);
+        f[r] = (g[r - 1] - (l >= 2 ? g[l - 2] : 0) + mod) % mod;
+        g[r] = (g[r - 1] + f[r]) % mod;
     }
+
+    return f[n];
 }
 ```
 
diff --git a/solution/3500-3599/3578.Count Partitions With Max-Min Difference at Most K/README_EN.md b/solution/3500-3599/3578.Count Partitions With Max-Min Difference at Most K/README_EN.md
index 092f645bfd37a..428a849b6de0b 100644
--- a/solution/3500-3599/3578.Count Partitions With Max-Min Difference at Most K/README_EN.md	
+++ b/solution/3500-3599/3578.Count Partitions With Max-Min Difference at Most K/README_EN.md	
@@ -213,643 +213,50 @@ func countPartitions(nums []int, k int) int {
 #### TypeScript
 
 ```ts
+import { AvlTree } from 'datastructures-js';
+
 function countPartitions(nums: number[], k: number): number {
-    const mod = 10 ** 9 + 7;
+    const mod = 1_000_000_007;
     const n = nums.length;
-    const sl = new TreapMultiSet<number>((a, b) => a - b);
-    const f: number[] = Array(n + 1).fill(0);
-    const g: number[] = Array(n + 1).fill(0);
-    f[0] = 1;
-    g[0] = 1;
-    for (let l = 1, r = 1; r <= n; ++r) {
-        const x = nums[r - 1];
-        sl.add(x);
-        while (sl.last()! - sl.first()! > k) {
-            sl.delete(nums[l - 1]);
-            l++;
-        }
-        f[r] = (g[r - 1] - (l >= 2 ? g[l - 2] : 0) + mod) % mod;
-        g[r] = (g[r - 1] + f[r]) % mod;
-    }
-    return f[n];
-}
-
-type CompareFunction<T, R extends 'number' | 'boolean'> = (
-    a: T,
-    b: T,
-) => R extends 'number' ? number : boolean;
-
-interface ITreapMultiSet<T> extends Iterable<T> {
-    add: (...value: T[]) => this;
-    has: (value: T) => boolean;
-    delete: (value: T) => void;
-
-    bisectLeft: (value: T) => number;
-    bisectRight: (value: T) => number;
-
-    indexOf: (value: T) => number;
-    lastIndexOf: (value: T) => number;
-
-    at: (index: number) => T | undefined;
-    first: () => T | undefined;
-    last: () => T | undefined;
-
-    lower: (value: T) => T | undefined;
-    higher: (value: T) => T | undefined;
-    floor: (value: T) => T | undefined;
-    ceil: (value: T) => T | undefined;
-
-    shift: () => T | undefined;
-    pop: (index?: number) => T | undefined;
-
-    count: (value: T) => number;
-
-    keys: () => IterableIterator<T>;
-    values: () => IterableIterator<T>;
-    rvalues: () => IterableIterator<T>;
-    entries: () => IterableIterator<[number, T]>;
-
-    readonly size: number;
-}
-
-class TreapNode<T = number> {
-    value: T;
-    count: number;
-    size: number;
-    priority: number;
-    left: TreapNode<T> | null;
-    right: TreapNode<T> | null;
-
-    constructor(value: T) {
-        this.value = value;
-        this.count = 1;
-        this.size = 1;
-        this.priority = Math.random();
-        this.left = null;
-        this.right = null;
-    }
-
-    static getSize(node: TreapNode<any> | null): number {
-        return node?.size ?? 0;
-    }
-
-    static getFac(node: TreapNode<any> | null): number {
-        return node?.priority ?? 0;
-    }
-
-    pushUp(): void {
-        let tmp = this.count;
-        tmp += TreapNode.getSize(this.left);
-        tmp += TreapNode.getSize(this.right);
-        this.size = tmp;
-    }
-
-    rotateRight(): TreapNode<T> {
-        // eslint-disable-next-line @typescript-eslint/no-this-alias
-        let node: TreapNode<T> = this;
-        const left = node.left;
-        node.left = left?.right ?? null;
-        left && (left.right = node);
-        left && (node = left);
-        node.right?.pushUp();
-        node.pushUp();
-        return node;
-    }
-
-    rotateLeft(): TreapNode<T> {
-        // eslint-disable-next-line @typescript-eslint/no-this-alias
-        let node: TreapNode<T> = this;
-        const right = node.right;
-        node.right = right?.left ?? null;
-        right && (right.left = node);
-        right && (node = right);
-        node.left?.pushUp();
-        node.pushUp();
-        return node;
-    }
-}
-
-class TreapMultiSet<T = number> implements ITreapMultiSet<T> {
-    private readonly root: TreapNode<T>;
-    private readonly compareFn: CompareFunction<T, 'number'>;
-    private readonly leftBound: T;
-    private readonly rightBound: T;
-
-    constructor(compareFn?: CompareFunction<T, 'number'>);
-    constructor(compareFn: CompareFunction<T, 'number'>, leftBound: T, rightBound: T);
-    constructor(
-        compareFn: CompareFunction<T, any> = (a: any, b: any) => a - b,
-        leftBound: any = -Infinity,
-        rightBound: any = Infinity,
-    ) {
-        this.root = new TreapNode<T>(rightBound);
-        this.root.priority = Infinity;
-        this.root.left = new TreapNode<T>(leftBound);
-        this.root.left.priority = -Infinity;
-        this.root.pushUp();
-
-        this.leftBound = leftBound;
-        this.rightBound = rightBound;
-        this.compareFn = compareFn;
-    }
-
-    get size(): number {
-        return this.root.size - 2;
-    }
-
-    get height(): number {
-        const getHeight = (node: TreapNode<T> | null): number => {
-            if (node == null) return 0;
-            return 1 + Math.max(getHeight(node.left), getHeight(node.right));
-        };
-
-        return getHeight(this.root);
-    }
-
-    /**
-     *
-     * @complexity `O(logn)`
-     * @description Returns true if value is a member.
-     */
-    has(value: T): boolean {
-        const compare = this.compareFn;
-        const dfs = (node: TreapNode<T> | null, value: T): boolean => {
-            if (node == null) return false;
-            if (compare(node.value, value) === 0) return true;
-            if (compare(node.value, value) < 0) return dfs(node.right, value);
-            return dfs(node.left, value);
-        };
-
-        return dfs(this.root, value);
-    }
-
-    /**
-     *
-     * @complexity `O(logn)`
-     * @description Add value to sorted set.
-     */
-    add(...values: T[]): this {
-        const compare = this.compareFn;
-        const dfs = (
-            node: TreapNode<T> | null,
-            value: T,
-            parent: TreapNode<T>,
-            direction: 'left' | 'right',
-        ): void => {
-            if (node == null) return;
-            if (compare(node.value, value) === 0) {
-                node.count++;
-                node.pushUp();
-            } else if (compare(node.value, value) > 0) {
-                if (node.left) {
-                    dfs(node.left, value, node, 'left');
-                } else {
-                    node.left = new TreapNode(value);
-                    node.pushUp();
-                }
-
-                if (TreapNode.getFac(node.left) > node.priority) {
-                    parent[direction] = node.rotateRight();
-                }
-            } else if (compare(node.value, value) < 0) {
-                if (node.right) {
-                    dfs(node.right, value, node, 'right');
-                } else {
-                    node.right = new TreapNode(value);
-                    node.pushUp();
-                }
-
-                if (TreapNode.getFac(node.right) > node.priority) {
-                    parent[direction] = node.rotateLeft();
-                }
-            }
-            parent.pushUp();
-        };
-
-        values.forEach(value => dfs(this.root.left, value, this.root, 'left'));
-        return this;
-    }
-
-    /**
-     *
-     * @complexity `O(logn)`
-     * @description Remove value from sorted set if it is a member.
-     * If value is not a member, do nothing.
-     */
-    delete(value: T): void {
-        const compare = this.compareFn;
-        const dfs = (
-            node: TreapNode<T> | null,
-            value: T,
-            parent: TreapNode<T>,
-            direction: 'left' | 'right',
-        ): void => {
-            if (node == null) return;
-
-            if (compare(node.value, value) === 0) {
-                if (node.count > 1) {
-                    node.count--;
-                    node?.pushUp();
-                } else if (node.left == null && node.right == null) {
-                    parent[direction] = null;
-                } else {
-                    // 旋到根节点
-                    if (
-                        node.right == null ||
-                        TreapNode.getFac(node.left) > TreapNode.getFac(node.right)
-                    ) {
-                        parent[direction] = node.rotateRight();
-                        dfs(parent[direction]?.right ?? null, value, parent[direction]!, 'right');
-                    } else {
-                        parent[direction] = node.rotateLeft();
-                        dfs(parent[direction]?.left ?? null, value, parent[direction]!, 'left');
-                    }
-                }
-            } else if (compare(node.value, value) > 0) {
-                dfs(node.left, value, node, 'left');
-            } else if (compare(node.value, value) < 0) {
-                dfs(node.right, value, node, 'right');
-            }
-
-            parent?.pushUp();
-        };
-
-        dfs(this.root.left, value, this.root, 'left');
-    }
-
-    /**
-     *
-     * @complexity `O(logn)`
-     * @description Returns an index to insert value in the sorted set.
-     * If the value is already present, the insertion point will be before (to the left of) any existing values.
-     */
-    bisectLeft(value: T): number {
-        const compare = this.compareFn;
-        const dfs = (node: TreapNode<T> | null, value: T): number => {
-            if (node == null) return 0;
-
-            if (compare(node.value, value) === 0) {
-                return TreapNode.getSize(node.left);
-            } else if (compare(node.value, value) > 0) {
-                return dfs(node.left, value);
-            } else if (compare(node.value, value) < 0) {
-                return dfs(node.right, value) + TreapNode.getSize(node.left) + node.count;
-            }
 
-            return 0;
-        };
+    const cnt = new Map<number, number>();
+    const st = new AvlTree<number>((a, b) => a - b);
 
-        return dfs(this.root, value) - 1;
-    }
-
-    /**
-     *
-     * @complexity `O(logn)`
-     * @description Returns an index to insert value in the sorted set.
-     * If the value is already present, the insertion point will be before (to the right of) any existing values.
-     */
-    bisectRight(value: T): number {
-        const compare = this.compareFn;
-        const dfs = (node: TreapNode<T> | null, value: T): number => {
-            if (node == null) return 0;
-
-            if (compare(node.value, value) === 0) {
-                return TreapNode.getSize(node.left) + node.count;
-            } else if (compare(node.value, value) > 0) {
-                return dfs(node.left, value);
-            } else if (compare(node.value, value) < 0) {
-                return dfs(node.right, value) + TreapNode.getSize(node.left) + node.count;
-            }
-
-            return 0;
-        };
-        return dfs(this.root, value) - 1;
-    }
-
-    /**
-     *
-     * @complexity `O(logn)`
-     * @description Returns the index of the first occurrence of a value in the set, or -1 if it is not present.
-     */
-    indexOf(value: T): number {
-        const compare = this.compareFn;
-        let isExist = false;
-
-        const dfs = (node: TreapNode<T> | null, value: T): number => {
-            if (node == null) return 0;
-
-            if (compare(node.value, value) === 0) {
-                isExist = true;
-                return TreapNode.getSize(node.left);
-            } else if (compare(node.value, value) > 0) {
-                return dfs(node.left, value);
-            } else if (compare(node.value, value) < 0) {
-                return dfs(node.right, value) + TreapNode.getSize(node.left) + node.count;
-            }
-
-            return 0;
-        };
-        const res = dfs(this.root, value) - 1;
-        return isExist ? res : -1;
-    }
-
-    /**
-     *
-     * @complexity `O(logn)`
-     * @description Returns the index of the last occurrence of a value in the set, or -1 if it is not present.
-     */
-    lastIndexOf(value: T): number {
-        const compare = this.compareFn;
-        let isExist = false;
-
-        const dfs = (node: TreapNode<T> | null, value: T): number => {
-            if (node == null) return 0;
-
-            if (compare(node.value, value) === 0) {
-                isExist = true;
-                return TreapNode.getSize(node.left) + node.count - 1;
-            } else if (compare(node.value, value) > 0) {
-                return dfs(node.left, value);
-            } else if (compare(node.value, value) < 0) {
-                return dfs(node.right, value) + TreapNode.getSize(node.left) + node.count;
-            }
-
-            return 0;
-        };
-
-        const res = dfs(this.root, value) - 1;
-        return isExist ? res : -1;
-    }
-
-    /**
-     *
-     * @complexity `O(logn)`
-     * @description Returns the item located at the specified index.
-     * @param index The zero-based index of the desired code unit. A negative index will count back from the last item.
-     */
-    at(index: number): T | undefined {
-        if (index < 0) index += this.size;
-        if (index < 0 || index >= this.size) return undefined;
-
-        const dfs = (node: TreapNode<T> | null, rank: number): T | undefined => {
-            if (node == null) return undefined;
-
-            if (TreapNode.getSize(node.left) >= rank) {
-                return dfs(node.left, rank);
-            } else if (TreapNode.getSize(node.left) + node.count >= rank) {
-                return node.value;
-            } else {
-                return dfs(node.right, rank - TreapNode.getSize(node.left) - node.count);
-            }
-        };
-
-        const res = dfs(this.root, index + 2);
-        return ([this.leftBound, this.rightBound] as any[]).includes(res) ? undefined : res;
-    }
-
-    /**
-     *
-     * @complexity `O(logn)`
-     * @description Find and return the element less than `val`, return `undefined` if no such element found.
-     */
-    lower(value: T): T | undefined {
-        const compare = this.compareFn;
-        const dfs = (node: TreapNode<T> | null, value: T): T | undefined => {
-            if (node == null) return undefined;
-            if (compare(node.value, value) >= 0) return dfs(node.left, value);
-
-            const tmp = dfs(node.right, value);
-            if (tmp == null || compare(node.value, tmp) > 0) {
-                return node.value;
-            } else {
-                return tmp;
-            }
-        };
-
-        const res = dfs(this.root, value) as any;
-        return res === this.leftBound ? undefined : res;
-    }
-
-    /**
-     *
-     * @complexity `O(logn)`
-     * @description Find and return the element greater than `val`, return `undefined` if no such element found.
-     */
-    higher(value: T): T | undefined {
-        const compare = this.compareFn;
-        const dfs = (node: TreapNode<T> | null, value: T): T | undefined => {
-            if (node == null) return undefined;
-            if (compare(node.value, value) <= 0) return dfs(node.right, value);
-
-            const tmp = dfs(node.left, value);
-
-            if (tmp == null || compare(node.value, tmp) < 0) {
-                return node.value;
-            } else {
-                return tmp;
-            }
-        };
-
-        const res = dfs(this.root, value) as any;
-        return res === this.rightBound ? undefined : res;
-    }
-
-    /**
-     *
-     * @complexity `O(logn)`
-     * @description Find and return the element less than or equal to `val`, return `undefined` if no such element found.
-     */
-    floor(value: T): T | undefined {
-        const compare = this.compareFn;
-        const dfs = (node: TreapNode<T> | null, value: T): T | undefined => {
-            if (node == null) return undefined;
-            if (compare(node.value, value) === 0) return node.value;
-            if (compare(node.value, value) >= 0) return dfs(node.left, value);
-
-            const tmp = dfs(node.right, value);
-            if (tmp == null || compare(node.value, tmp) > 0) {
-                return node.value;
-            } else {
-                return tmp;
-            }
-        };
-
-        const res = dfs(this.root, value) as any;
-        return res === this.leftBound ? undefined : res;
-    }
-
-    /**
-     *
-     * @complexity `O(logn)`
-     * @description Find and return the element greater than or equal to `val`, return `undefined` if no such element found.
-     */
-    ceil(value: T): T | undefined {
-        const compare = this.compareFn;
-        const dfs = (node: TreapNode<T> | null, value: T): T | undefined => {
-            if (node == null) return undefined;
-            if (compare(node.value, value) === 0) return node.value;
-            if (compare(node.value, value) <= 0) return dfs(node.right, value);
-
-            const tmp = dfs(node.left, value);
-
-            if (tmp == null || compare(node.value, tmp) < 0) {
-                return node.value;
-            } else {
-                return tmp;
-            }
-        };
-
-        const res = dfs(this.root, value) as any;
-        return res === this.rightBound ? undefined : res;
-    }
-
-    /**
-     * @complexity `O(logn)`
-     * @description
-     * Returns the last element from set.
-     * If the set is empty, undefined is returned.
-     */
-    first(): T | undefined {
-        const iter = this.inOrder();
-        iter.next();
-        const res = iter.next().value;
-        return res === this.rightBound ? undefined : res;
-    }
-
-    /**
-     * @complexity `O(logn)`
-     * @description
-     * Returns the last element from set.
-     * If the set is empty, undefined is returned .
-     */
-    last(): T | undefined {
-        const iter = this.reverseInOrder();
-        iter.next();
-        const res = iter.next().value;
-        return res === this.leftBound ? undefined : res;
-    }
-
-    /**
-     * @complexity `O(logn)`
-     * @description
-     * Removes the first element from an set and returns it.
-     * If the set is empty, undefined is returned and the set is not modified.
-     */
-    shift(): T | undefined {
-        const first = this.first();
-        if (first === undefined) return undefined;
-        this.delete(first);
-        return first;
-    }
-
-    /**
-     * @complexity `O(logn)`
-     * @description
-     * Removes the last element from an set and returns it.
-     * If the set is empty, undefined is returned and the set is not modified.
-     */
-    pop(index?: number): T | undefined {
-        if (index == null) {
-            const last = this.last();
-            if (last === undefined) return undefined;
-            this.delete(last);
-            return last;
+    function insert(x: number) {
+        const c = (cnt.get(x) || 0) + 1;
+        cnt.set(x, c);
+        if (c === 1) {
+            st.insert(x);
         }
-
-        const toDelete = this.at(index);
-        if (toDelete == null) return;
-        this.delete(toDelete);
-        return toDelete;
-    }
-
-    /**
-     *
-     * @complexity `O(logn)`
-     * @description
-     * Returns number of occurrences of value in the sorted set.
-     */
-    count(value: T): number {
-        const compare = this.compareFn;
-        const dfs = (node: TreapNode<T> | null, value: T): number => {
-            if (node == null) return 0;
-            if (compare(node.value, value) === 0) return node.count;
-            if (compare(node.value, value) < 0) return dfs(node.right, value);
-            return dfs(node.left, value);
-        };
-
-        return dfs(this.root, value);
-    }
-
-    *[Symbol.iterator](): Generator<T, any, any> {
-        yield* this.values();
-    }
-
-    /**
-     * @description
-     * Returns an iterable of keys in the set.
-     */
-    *keys(): Generator<T, any, any> {
-        yield* this.values();
     }
 
-    /**
-     * @description
-     * Returns an iterable of values in the set.
-     */
-    *values(): Generator<T, any, any> {
-        const iter = this.inOrder();
-        iter.next();
-        const steps = this.size;
-        for (let _ = 0; _ < steps; _++) {
-            yield iter.next().value;
+    function erase(x: number) {
+        const c = cnt.get(x)! - 1;
+        cnt.set(x, c);
+        if (c === 0) {
+            st.remove(x);
         }
     }
 
-    /**
-     * @description
-     * Returns a generator for reversed order traversing the set.
-     */
-    *rvalues(): Generator<T, any, any> {
-        const iter = this.reverseInOrder();
-        iter.next();
-        const steps = this.size;
-        for (let _ = 0; _ < steps; _++) {
-            yield iter.next().value;
-        }
-    }
+    const f = Array(n + 1).fill(0);
+    const g = Array(n + 1).fill(0);
+    f[0] = 1;
+    g[0] = 1;
 
-    /**
-     * @description
-     * Returns an iterable of key, value pairs for every entry in the set.
-     */
-    *entries(): IterableIterator<[number, T]> {
-        const iter = this.inOrder();
-        iter.next();
-        const steps = this.size;
-        for (let i = 0; i < steps; i++) {
-            yield [i, iter.next().value];
-        }
-    }
+    for (let l = 1, r = 1; r <= n; ++r) {
+        const x = nums[r - 1];
+        insert(x);
 
-    private *inOrder(root: TreapNode<T> | null = this.root): Generator<T, any, any> {
-        if (root == null) return;
-        yield* this.inOrder(root.left);
-        const count = root.count;
-        for (let _ = 0; _ < count; _++) {
-            yield root.value;
+        while (st.max()!.getValue() - st.min()!.getValue() > k) {
+            erase(nums[l - 1]);
+            l++;
         }
-        yield* this.inOrder(root.right);
-    }
 
-    private *reverseInOrder(root: TreapNode<T> | null = this.root): Generator<T, any, any> {
-        if (root == null) return;
-        yield* this.reverseInOrder(root.right);
-        const count = root.count;
-        for (let _ = 0; _ < count; _++) {
-            yield root.value;
-        }
-        yield* this.reverseInOrder(root.left);
+        f[r] = (g[r - 1] - (l >= 2 ? g[l - 2] : 0) + mod) % mod;
+        g[r] = (g[r - 1] + f[r]) % mod;
     }
+
+    return f[n];
 }
 ```
 
diff --git a/solution/3500-3599/3578.Count Partitions With Max-Min Difference at Most K/Solution.ts b/solution/3500-3599/3578.Count Partitions With Max-Min Difference at Most K/Solution.ts
index 6d9aeb3087e2c..34286df6b21f2 100644
--- a/solution/3500-3599/3578.Count Partitions With Max-Min Difference at Most K/Solution.ts	
+++ b/solution/3500-3599/3578.Count Partitions With Max-Min Difference at Most K/Solution.ts	
@@ -1,638 +1,45 @@
+import { AvlTree } from 'datastructures-js';
+
 function countPartitions(nums: number[], k: number): number {
-    const mod = 10 ** 9 + 7;
+    const mod = 1_000_000_007;
     const n = nums.length;
-    const sl = new TreapMultiSet<number>((a, b) => a - b);
-    const f: number[] = Array(n + 1).fill(0);
-    const g: number[] = Array(n + 1).fill(0);
-    f[0] = 1;
-    g[0] = 1;
-    for (let l = 1, r = 1; r <= n; ++r) {
-        const x = nums[r - 1];
-        sl.add(x);
-        while (sl.last()! - sl.first()! > k) {
-            sl.delete(nums[l - 1]);
-            l++;
-        }
-        f[r] = (g[r - 1] - (l >= 2 ? g[l - 2] : 0) + mod) % mod;
-        g[r] = (g[r - 1] + f[r]) % mod;
-    }
-    return f[n];
-}
-
-type CompareFunction<T, R extends 'number' | 'boolean'> = (
-    a: T,
-    b: T,
-) => R extends 'number' ? number : boolean;
-
-interface ITreapMultiSet<T> extends Iterable<T> {
-    add: (...value: T[]) => this;
-    has: (value: T) => boolean;
-    delete: (value: T) => void;
-
-    bisectLeft: (value: T) => number;
-    bisectRight: (value: T) => number;
-
-    indexOf: (value: T) => number;
-    lastIndexOf: (value: T) => number;
-
-    at: (index: number) => T | undefined;
-    first: () => T | undefined;
-    last: () => T | undefined;
-
-    lower: (value: T) => T | undefined;
-    higher: (value: T) => T | undefined;
-    floor: (value: T) => T | undefined;
-    ceil: (value: T) => T | undefined;
-
-    shift: () => T | undefined;
-    pop: (index?: number) => T | undefined;
-
-    count: (value: T) => number;
-
-    keys: () => IterableIterator<T>;
-    values: () => IterableIterator<T>;
-    rvalues: () => IterableIterator<T>;
-    entries: () => IterableIterator<[number, T]>;
-
-    readonly size: number;
-}
-
-class TreapNode<T = number> {
-    value: T;
-    count: number;
-    size: number;
-    priority: number;
-    left: TreapNode<T> | null;
-    right: TreapNode<T> | null;
-
-    constructor(value: T) {
-        this.value = value;
-        this.count = 1;
-        this.size = 1;
-        this.priority = Math.random();
-        this.left = null;
-        this.right = null;
-    }
-
-    static getSize(node: TreapNode<any> | null): number {
-        return node?.size ?? 0;
-    }
-
-    static getFac(node: TreapNode<any> | null): number {
-        return node?.priority ?? 0;
-    }
-
-    pushUp(): void {
-        let tmp = this.count;
-        tmp += TreapNode.getSize(this.left);
-        tmp += TreapNode.getSize(this.right);
-        this.size = tmp;
-    }
-
-    rotateRight(): TreapNode<T> {
-        // eslint-disable-next-line @typescript-eslint/no-this-alias
-        let node: TreapNode<T> = this;
-        const left = node.left;
-        node.left = left?.right ?? null;
-        left && (left.right = node);
-        left && (node = left);
-        node.right?.pushUp();
-        node.pushUp();
-        return node;
-    }
-
-    rotateLeft(): TreapNode<T> {
-        // eslint-disable-next-line @typescript-eslint/no-this-alias
-        let node: TreapNode<T> = this;
-        const right = node.right;
-        node.right = right?.left ?? null;
-        right && (right.left = node);
-        right && (node = right);
-        node.left?.pushUp();
-        node.pushUp();
-        return node;
-    }
-}
-
-class TreapMultiSet<T = number> implements ITreapMultiSet<T> {
-    private readonly root: TreapNode<T>;
-    private readonly compareFn: CompareFunction<T, 'number'>;
-    private readonly leftBound: T;
-    private readonly rightBound: T;
-
-    constructor(compareFn?: CompareFunction<T, 'number'>);
-    constructor(compareFn: CompareFunction<T, 'number'>, leftBound: T, rightBound: T);
-    constructor(
-        compareFn: CompareFunction<T, any> = (a: any, b: any) => a - b,
-        leftBound: any = -Infinity,
-        rightBound: any = Infinity,
-    ) {
-        this.root = new TreapNode<T>(rightBound);
-        this.root.priority = Infinity;
-        this.root.left = new TreapNode<T>(leftBound);
-        this.root.left.priority = -Infinity;
-        this.root.pushUp();
-
-        this.leftBound = leftBound;
-        this.rightBound = rightBound;
-        this.compareFn = compareFn;
-    }
-
-    get size(): number {
-        return this.root.size - 2;
-    }
-
-    get height(): number {
-        const getHeight = (node: TreapNode<T> | null): number => {
-            if (node == null) return 0;
-            return 1 + Math.max(getHeight(node.left), getHeight(node.right));
-        };
-
-        return getHeight(this.root);
-    }
-
-    /**
-     *
-     * @complexity `O(logn)`
-     * @description Returns true if value is a member.
-     */
-    has(value: T): boolean {
-        const compare = this.compareFn;
-        const dfs = (node: TreapNode<T> | null, value: T): boolean => {
-            if (node == null) return false;
-            if (compare(node.value, value) === 0) return true;
-            if (compare(node.value, value) < 0) return dfs(node.right, value);
-            return dfs(node.left, value);
-        };
-
-        return dfs(this.root, value);
-    }
-
-    /**
-     *
-     * @complexity `O(logn)`
-     * @description Add value to sorted set.
-     */
-    add(...values: T[]): this {
-        const compare = this.compareFn;
-        const dfs = (
-            node: TreapNode<T> | null,
-            value: T,
-            parent: TreapNode<T>,
-            direction: 'left' | 'right',
-        ): void => {
-            if (node == null) return;
-            if (compare(node.value, value) === 0) {
-                node.count++;
-                node.pushUp();
-            } else if (compare(node.value, value) > 0) {
-                if (node.left) {
-                    dfs(node.left, value, node, 'left');
-                } else {
-                    node.left = new TreapNode(value);
-                    node.pushUp();
-                }
-
-                if (TreapNode.getFac(node.left) > node.priority) {
-                    parent[direction] = node.rotateRight();
-                }
-            } else if (compare(node.value, value) < 0) {
-                if (node.right) {
-                    dfs(node.right, value, node, 'right');
-                } else {
-                    node.right = new TreapNode(value);
-                    node.pushUp();
-                }
-
-                if (TreapNode.getFac(node.right) > node.priority) {
-                    parent[direction] = node.rotateLeft();
-                }
-            }
-            parent.pushUp();
-        };
-
-        values.forEach(value => dfs(this.root.left, value, this.root, 'left'));
-        return this;
-    }
-
-    /**
-     *
-     * @complexity `O(logn)`
-     * @description Remove value from sorted set if it is a member.
-     * If value is not a member, do nothing.
-     */
-    delete(value: T): void {
-        const compare = this.compareFn;
-        const dfs = (
-            node: TreapNode<T> | null,
-            value: T,
-            parent: TreapNode<T>,
-            direction: 'left' | 'right',
-        ): void => {
-            if (node == null) return;
-
-            if (compare(node.value, value) === 0) {
-                if (node.count > 1) {
-                    node.count--;
-                    node?.pushUp();
-                } else if (node.left == null && node.right == null) {
-                    parent[direction] = null;
-                } else {
-                    // 旋到根节点
-                    if (
-                        node.right == null ||
-                        TreapNode.getFac(node.left) > TreapNode.getFac(node.right)
-                    ) {
-                        parent[direction] = node.rotateRight();
-                        dfs(parent[direction]?.right ?? null, value, parent[direction]!, 'right');
-                    } else {
-                        parent[direction] = node.rotateLeft();
-                        dfs(parent[direction]?.left ?? null, value, parent[direction]!, 'left');
-                    }
-                }
-            } else if (compare(node.value, value) > 0) {
-                dfs(node.left, value, node, 'left');
-            } else if (compare(node.value, value) < 0) {
-                dfs(node.right, value, node, 'right');
-            }
-
-            parent?.pushUp();
-        };
-
-        dfs(this.root.left, value, this.root, 'left');
-    }
-
-    /**
-     *
-     * @complexity `O(logn)`
-     * @description Returns an index to insert value in the sorted set.
-     * If the value is already present, the insertion point will be before (to the left of) any existing values.
-     */
-    bisectLeft(value: T): number {
-        const compare = this.compareFn;
-        const dfs = (node: TreapNode<T> | null, value: T): number => {
-            if (node == null) return 0;
-
-            if (compare(node.value, value) === 0) {
-                return TreapNode.getSize(node.left);
-            } else if (compare(node.value, value) > 0) {
-                return dfs(node.left, value);
-            } else if (compare(node.value, value) < 0) {
-                return dfs(node.right, value) + TreapNode.getSize(node.left) + node.count;
-            }
-
-            return 0;
-        };
-
-        return dfs(this.root, value) - 1;
-    }
-
-    /**
-     *
-     * @complexity `O(logn)`
-     * @description Returns an index to insert value in the sorted set.
-     * If the value is already present, the insertion point will be before (to the right of) any existing values.
-     */
-    bisectRight(value: T): number {
-        const compare = this.compareFn;
-        const dfs = (node: TreapNode<T> | null, value: T): number => {
-            if (node == null) return 0;
 
-            if (compare(node.value, value) === 0) {
-                return TreapNode.getSize(node.left) + node.count;
-            } else if (compare(node.value, value) > 0) {
-                return dfs(node.left, value);
-            } else if (compare(node.value, value) < 0) {
-                return dfs(node.right, value) + TreapNode.getSize(node.left) + node.count;
-            }
+    const cnt = new Map<number, number>();
+    const st = new AvlTree<number>((a, b) => a - b);
 
-            return 0;
-        };
-        return dfs(this.root, value) - 1;
-    }
-
-    /**
-     *
-     * @complexity `O(logn)`
-     * @description Returns the index of the first occurrence of a value in the set, or -1 if it is not present.
-     */
-    indexOf(value: T): number {
-        const compare = this.compareFn;
-        let isExist = false;
-
-        const dfs = (node: TreapNode<T> | null, value: T): number => {
-            if (node == null) return 0;
-
-            if (compare(node.value, value) === 0) {
-                isExist = true;
-                return TreapNode.getSize(node.left);
-            } else if (compare(node.value, value) > 0) {
-                return dfs(node.left, value);
-            } else if (compare(node.value, value) < 0) {
-                return dfs(node.right, value) + TreapNode.getSize(node.left) + node.count;
-            }
-
-            return 0;
-        };
-        const res = dfs(this.root, value) - 1;
-        return isExist ? res : -1;
-    }
-
-    /**
-     *
-     * @complexity `O(logn)`
-     * @description Returns the index of the last occurrence of a value in the set, or -1 if it is not present.
-     */
-    lastIndexOf(value: T): number {
-        const compare = this.compareFn;
-        let isExist = false;
-
-        const dfs = (node: TreapNode<T> | null, value: T): number => {
-            if (node == null) return 0;
-
-            if (compare(node.value, value) === 0) {
-                isExist = true;
-                return TreapNode.getSize(node.left) + node.count - 1;
-            } else if (compare(node.value, value) > 0) {
-                return dfs(node.left, value);
-            } else if (compare(node.value, value) < 0) {
-                return dfs(node.right, value) + TreapNode.getSize(node.left) + node.count;
-            }
-
-            return 0;
-        };
-
-        const res = dfs(this.root, value) - 1;
-        return isExist ? res : -1;
-    }
-
-    /**
-     *
-     * @complexity `O(logn)`
-     * @description Returns the item located at the specified index.
-     * @param index The zero-based index of the desired code unit. A negative index will count back from the last item.
-     */
-    at(index: number): T | undefined {
-        if (index < 0) index += this.size;
-        if (index < 0 || index >= this.size) return undefined;
-
-        const dfs = (node: TreapNode<T> | null, rank: number): T | undefined => {
-            if (node == null) return undefined;
-
-            if (TreapNode.getSize(node.left) >= rank) {
-                return dfs(node.left, rank);
-            } else if (TreapNode.getSize(node.left) + node.count >= rank) {
-                return node.value;
-            } else {
-                return dfs(node.right, rank - TreapNode.getSize(node.left) - node.count);
-            }
-        };
-
-        const res = dfs(this.root, index + 2);
-        return ([this.leftBound, this.rightBound] as any[]).includes(res) ? undefined : res;
-    }
-
-    /**
-     *
-     * @complexity `O(logn)`
-     * @description Find and return the element less than `val`, return `undefined` if no such element found.
-     */
-    lower(value: T): T | undefined {
-        const compare = this.compareFn;
-        const dfs = (node: TreapNode<T> | null, value: T): T | undefined => {
-            if (node == null) return undefined;
-            if (compare(node.value, value) >= 0) return dfs(node.left, value);
-
-            const tmp = dfs(node.right, value);
-            if (tmp == null || compare(node.value, tmp) > 0) {
-                return node.value;
-            } else {
-                return tmp;
-            }
-        };
-
-        const res = dfs(this.root, value) as any;
-        return res === this.leftBound ? undefined : res;
-    }
-
-    /**
-     *
-     * @complexity `O(logn)`
-     * @description Find and return the element greater than `val`, return `undefined` if no such element found.
-     */
-    higher(value: T): T | undefined {
-        const compare = this.compareFn;
-        const dfs = (node: TreapNode<T> | null, value: T): T | undefined => {
-            if (node == null) return undefined;
-            if (compare(node.value, value) <= 0) return dfs(node.right, value);
-
-            const tmp = dfs(node.left, value);
-
-            if (tmp == null || compare(node.value, tmp) < 0) {
-                return node.value;
-            } else {
-                return tmp;
-            }
-        };
-
-        const res = dfs(this.root, value) as any;
-        return res === this.rightBound ? undefined : res;
-    }
-
-    /**
-     *
-     * @complexity `O(logn)`
-     * @description Find and return the element less than or equal to `val`, return `undefined` if no such element found.
-     */
-    floor(value: T): T | undefined {
-        const compare = this.compareFn;
-        const dfs = (node: TreapNode<T> | null, value: T): T | undefined => {
-            if (node == null) return undefined;
-            if (compare(node.value, value) === 0) return node.value;
-            if (compare(node.value, value) >= 0) return dfs(node.left, value);
-
-            const tmp = dfs(node.right, value);
-            if (tmp == null || compare(node.value, tmp) > 0) {
-                return node.value;
-            } else {
-                return tmp;
-            }
-        };
-
-        const res = dfs(this.root, value) as any;
-        return res === this.leftBound ? undefined : res;
-    }
-
-    /**
-     *
-     * @complexity `O(logn)`
-     * @description Find and return the element greater than or equal to `val`, return `undefined` if no such element found.
-     */
-    ceil(value: T): T | undefined {
-        const compare = this.compareFn;
-        const dfs = (node: TreapNode<T> | null, value: T): T | undefined => {
-            if (node == null) return undefined;
-            if (compare(node.value, value) === 0) return node.value;
-            if (compare(node.value, value) <= 0) return dfs(node.right, value);
-
-            const tmp = dfs(node.left, value);
-
-            if (tmp == null || compare(node.value, tmp) < 0) {
-                return node.value;
-            } else {
-                return tmp;
-            }
-        };
-
-        const res = dfs(this.root, value) as any;
-        return res === this.rightBound ? undefined : res;
-    }
-
-    /**
-     * @complexity `O(logn)`
-     * @description
-     * Returns the last element from set.
-     * If the set is empty, undefined is returned.
-     */
-    first(): T | undefined {
-        const iter = this.inOrder();
-        iter.next();
-        const res = iter.next().value;
-        return res === this.rightBound ? undefined : res;
-    }
-
-    /**
-     * @complexity `O(logn)`
-     * @description
-     * Returns the last element from set.
-     * If the set is empty, undefined is returned .
-     */
-    last(): T | undefined {
-        const iter = this.reverseInOrder();
-        iter.next();
-        const res = iter.next().value;
-        return res === this.leftBound ? undefined : res;
-    }
-
-    /**
-     * @complexity `O(logn)`
-     * @description
-     * Removes the first element from an set and returns it.
-     * If the set is empty, undefined is returned and the set is not modified.
-     */
-    shift(): T | undefined {
-        const first = this.first();
-        if (first === undefined) return undefined;
-        this.delete(first);
-        return first;
-    }
-
-    /**
-     * @complexity `O(logn)`
-     * @description
-     * Removes the last element from an set and returns it.
-     * If the set is empty, undefined is returned and the set is not modified.
-     */
-    pop(index?: number): T | undefined {
-        if (index == null) {
-            const last = this.last();
-            if (last === undefined) return undefined;
-            this.delete(last);
-            return last;
+    function insert(x: number) {
+        const c = (cnt.get(x) || 0) + 1;
+        cnt.set(x, c);
+        if (c === 1) {
+            st.insert(x);
         }
-
-        const toDelete = this.at(index);
-        if (toDelete == null) return;
-        this.delete(toDelete);
-        return toDelete;
-    }
-
-    /**
-     *
-     * @complexity `O(logn)`
-     * @description
-     * Returns number of occurrences of value in the sorted set.
-     */
-    count(value: T): number {
-        const compare = this.compareFn;
-        const dfs = (node: TreapNode<T> | null, value: T): number => {
-            if (node == null) return 0;
-            if (compare(node.value, value) === 0) return node.count;
-            if (compare(node.value, value) < 0) return dfs(node.right, value);
-            return dfs(node.left, value);
-        };
-
-        return dfs(this.root, value);
-    }
-
-    *[Symbol.iterator](): Generator<T, any, any> {
-        yield* this.values();
-    }
-
-    /**
-     * @description
-     * Returns an iterable of keys in the set.
-     */
-    *keys(): Generator<T, any, any> {
-        yield* this.values();
     }
 
-    /**
-     * @description
-     * Returns an iterable of values in the set.
-     */
-    *values(): Generator<T, any, any> {
-        const iter = this.inOrder();
-        iter.next();
-        const steps = this.size;
-        for (let _ = 0; _ < steps; _++) {
-            yield iter.next().value;
+    function erase(x: number) {
+        const c = cnt.get(x)! - 1;
+        cnt.set(x, c);
+        if (c === 0) {
+            st.remove(x);
         }
     }
 
-    /**
-     * @description
-     * Returns a generator for reversed order traversing the set.
-     */
-    *rvalues(): Generator<T, any, any> {
-        const iter = this.reverseInOrder();
-        iter.next();
-        const steps = this.size;
-        for (let _ = 0; _ < steps; _++) {
-            yield iter.next().value;
-        }
-    }
+    const f = Array(n + 1).fill(0);
+    const g = Array(n + 1).fill(0);
+    f[0] = 1;
+    g[0] = 1;
 
-    /**
-     * @description
-     * Returns an iterable of key, value pairs for every entry in the set.
-     */
-    *entries(): IterableIterator<[number, T]> {
-        const iter = this.inOrder();
-        iter.next();
-        const steps = this.size;
-        for (let i = 0; i < steps; i++) {
-            yield [i, iter.next().value];
-        }
-    }
+    for (let l = 1, r = 1; r <= n; ++r) {
+        const x = nums[r - 1];
+        insert(x);
 
-    private *inOrder(root: TreapNode<T> | null = this.root): Generator<T, any, any> {
-        if (root == null) return;
-        yield* this.inOrder(root.left);
-        const count = root.count;
-        for (let _ = 0; _ < count; _++) {
-            yield root.value;
+        while (st.max()!.getValue() - st.min()!.getValue() > k) {
+            erase(nums[l - 1]);
+            l++;
         }
-        yield* this.inOrder(root.right);
-    }
 
-    private *reverseInOrder(root: TreapNode<T> | null = this.root): Generator<T, any, any> {
-        if (root == null) return;
-        yield* this.reverseInOrder(root.right);
-        const count = root.count;
-        for (let _ = 0; _ < count; _++) {
-            yield root.value;
-        }
-        yield* this.reverseInOrder(root.left);
+        f[r] = (g[r - 1] - (l >= 2 ? g[l - 2] : 0) + mod) % mod;
+        g[r] = (g[r - 1] + f[r]) % mod;
     }
+
+    return f[n];
 }