2465-NumberOfDistinctAverages.go

package main

// 2465. Number of Distinct Averages
// You are given a 0-indexed integer array nums of even length.

// As long as nums is not empty, you must repetitively:
//     Find the minimum number in nums and remove it.
//     Find the maximum number in nums and remove it.
//     Calculate the average of the two removed numbers.

// The average of two numbers a and b is (a + b) / 2.
//     For example, the average of 2 and 3 is (2 + 3) / 2 = 2.5.

// Return the number of distinct averages calculated using the above process.

// Note that when there is a tie for a minimum or maximum number, any can be removed.

// Example 1:
// Input: nums = [4,1,4,0,3,5]
// Output: 2
// Explanation:
// 1. Remove 0 and 5, and the average is (0 + 5) / 2 = 2.5. Now, nums = [4,1,4,3].
// 2. Remove 1 and 4. The average is (1 + 4) / 2 = 2.5, and nums = [4,3].
// 3. Remove 3 and 4, and the average is (3 + 4) / 2 = 3.5.
// Since there are 2 distinct numbers among 2.5, 2.5, and 3.5, we return 2.

// Example 2:
// Input: nums = [1,100]
// Output: 1
// Explanation:
// There is only one average to be calculated after removing 1 and 100, so we return 1.

// Constraints:
//     2 <= nums.length <= 100
//     nums.length is even.
//     0 <= nums[i] <= 100

import "fmt"
import "sort"

func distinctAverages(nums []int) int {
    sort.Ints(nums)
    arr := make(map[int]bool, len(nums) / 2)
    for l, r := 0, len(nums) - 1; l < r; l, r = l + 1, r - 1 {
        arr[nums[l] + nums[r]] = true
    }
    return len(arr)
}

func main() {
    // Example 1:
    // Input: nums = [4,1,4,0,3,5]
    // Output: 2
    // Explanation:
    // 1. Remove 0 and 5, and the average is (0 + 5) / 2 = 2.5. Now, nums = [4,1,4,3].
    // 2. Remove 1 and 4. The average is (1 + 4) / 2 = 2.5, and nums = [4,3].
    // 3. Remove 3 and 4, and the average is (3 + 4) / 2 = 3.5.
    // Since there are 2 distinct numbers among 2.5, 2.5, and 3.5, we return 2.
    fmt.Println(distinctAverages([]int{4,1,4,0,3,5})) // 2
    // Example 2:
    // Input: nums = [1,100]
    // Output: 1
    // Explanation:
    // There is only one average to be calculated after removing 1 and 100, so we return 1.
    fmt.Println(distinctAverages([]int{1,100})) // 1
}