2366-MinimumReplacementsToSortTheArray.go

package main

// 2366. Minimum Replacements to Sort the Array
// You are given a 0-indexed integer array nums. 
// In one operation you can replace any element of the array with any two elements that sum to it.
//     For example, consider nums = [5,6,7]. 
//     In one operation, we can replace nums[1] with 2 and 4 and convert nums to [5,2,4,7].

// Return the minimum number of operations to make an array that is sorted in non-decreasing order.

// Example 1:
// Input: nums = [3,9,3]
// Output: 2
// Explanation: Here are the steps to sort the array in non-decreasing order:
// - From [3,9,3], replace the 9 with 3 and 6 so the array becomes [3,3,6,3]
// - From [3,3,6,3], replace the 6 with 3 and 3 so the array becomes [3,3,3,3,3]
// There are 2 steps to sort the array in non-decreasing order. Therefore, we return 2.

// Example 2:
// Input: nums = [1,2,3,4,5]
// Output: 0
// Explanation: The array is already in non-decreasing order. Therefore, we return 0. 

// Constraints:
//     1 <= nums.length <= 10^5
//     1 <= nums[i] <= 10^9

import "fmt"

func minimumReplacement(nums []int) int64 {
    res, prev := 0, nums[len(nums) - 1]
    for i := len(nums) - 2; i >= 0; i-- {
        val := (nums[i] + prev - 1) / prev
        res += (val - 1)
        prev = nums[i] / val
    }
    return int64(res)
}

func minimumReplacement1(nums []int) int64 {
    res, right := 0, nums[len(nums) - 1]
    for i := len(nums) - 2; i >= 0; i-- {
        if nums[i] > right {
            parts := (nums[i] + right - 1) / right
            res += (parts - 1)
            right = nums[i] / parts
        } else {
            right = nums[i]
        }
    }
    return int64(res)
}

func main() {
    // Example 1:
    // Input: nums = [3,9,3]
    // Output: 2
    // Explanation: Here are the steps to sort the array in non-decreasing order:
    // - From [3,9,3], replace the 9 with 3 and 6 so the array becomes [3,3,6,3]
    // - From [3,3,6,3], replace the 6 with 3 and 3 so the array becomes [3,3,3,3,3]
    // There are 2 steps to sort the array in non-decreasing order. Therefore, we return 2.
    fmt.Println(minimumReplacement([]int{3,9,3})) // 2
    // Example 2:
    // Input: nums = [1,2,3,4,5]
    // Output: 0
    // Explanation: The array is already in non-decreasing order. Therefore, we return 0. 
    fmt.Println(minimumReplacement([]int{1,2,3,4,5})) // 0

    fmt.Println(minimumReplacement1([]int{3,9,3})) // 2
    fmt.Println(minimumReplacement1([]int{1,2,3,4,5})) // 0
}