Merge pull request #22 from linux-nerd/feature/#21_add_height_to_BST

added height method to bst

Author: linux-nerd

src/binary-search-tree/binary-search-tree.js

@@ -31,6 +31,7 @@ export class BSTNode {
   /* Getter and Setter for right sub tree */
   get right() { return this._right; }
   set right(right) { this._right = right; }
+
 }
 
 /**
@@ -179,6 +180,19 @@ export class BST {
     return response;
   }
 
+  /**
+   * Returns height of the Node
+   * @param {BST} node
+   * @return {number} height
+   */
+  height(node = this.root) {
+    if (node === null) {
+      return -1;
+    }
+
+    return Math.max(this.height(node.left), this.height(node.right)) + 1;
+  }
+
   /**
    * Print the values of the BST in specific order
    * @param {string} type - value of type can be inOrder, preOrder, postOrder, levelOrder

src/binary-search-tree/binary-search-tree.spec.js

@@ -16,6 +16,31 @@ describe('Binary Search Tree', () => {
     expect(bst.len).toBe(0);
   });
 
+  describe('Height of the node', () => {
+    beforeEach(() => {
+      bst.insert(5);
+      bst.insert(6);
+      bst.insert(4);
+      bst.insert(2);
+    });
+
+    it('should have height of node 4 as 1', () => {
+      expect(bst.height(bst.lookup(4).currentNode)).toBe(1);
+    });
+
+    it('should have height of tree = 2', () => {
+      expect(bst.height()).toBe(2);
+    });
+
+    it('should have height 0 of leaf nodes', () => {
+      expect(bst.height(bst.lookup(6).currentNode)).toBe(0);
+    });
+
+    it('should have height 0 of leaf nodes', () => {
+      expect(bst.height(bst.lookup(2).currentNode)).toBe(0);
+    });
+  });
+
   describe('Insertion operation', () => {
     it('should insert values in the BST', () => {
       bst.insert(5);