1827-MinimumOperationsToMakeTheArrayIncreasing.go

package main

// 1827. Minimum Operations to Make the Array Increasing
// You are given an integer array nums (0-indexed). 
// In one operation, you can choose an element of the array and increment it by 1.
//     For example, if nums = [1,2,3], you can choose to increment nums[1] to make nums = [1,3,3].

// Return the minimum number of operations needed to make nums strictly increasing.

// An array nums is strictly increasing if nums[i] < nums[i+1] for all 0 <= i < nums.length - 1. 
// An array of length 1 is trivially strictly increasing.

// Example 1:
// Input: nums = [1,1,1]
// Output: 3
// Explanation: You can do the following operations:
// 1) Increment nums[2], so nums becomes [1,1,2].
// 2) Increment nums[1], so nums becomes [1,2,2].
// 3) Increment nums[2], so nums becomes [1,2,3].

// Example 2:
// Input: nums = [1,5,2,4,1]
// Output: 14

// Example 3:
// Input: nums = [8]
// Output: 0

// Constraints:
//     1 <= nums.length <= 5000
//     1 <= nums[i] <= 10^4

import "fmt"

func minOperations(nums []int) int {
    if len(nums) == 1 { return 0 }
    res := 0
    for i := 1; i < len(nums); i++ {
        for nums[i - 1] >= nums[i] {
            diff := nums[i - 1] - nums[i] + 1
            nums[i] += diff
            res += diff
        }
    }
    return res
}

func minOperations1(nums []int) int {
    if len(nums) == 1 { return 0 }
    res, num := 0, 0
    for _, v := range nums {
        if v <= num {
            res += num + 1 - v
            v = num + 1
        }
        num = v
    }
    return res
}

func main() {
    // Example 1:
    // Input: nums = [1,1,1]
    // Output: 3
    // Explanation: You can do the following operations:
    // 1) Increment nums[2], so nums becomes [1,1,2].
    // 2) Increment nums[1], so nums becomes [1,2,2].
    // 3) Increment nums[2], so nums becomes [1,2,3].
    fmt.Println(minOperations([]int{1,1,1})) // 3
    // Example 2:
    // Input: nums = [1,5,2,4,1]
    // Output: 14
    fmt.Println(minOperations([]int{1,5,2,4,1})) // 14
    // Example 3:
    // Input: nums = [8]
    // Output: 0
    fmt.Println(minOperations([]int{8})) // 0

    fmt.Println(minOperations1([]int{1,1,1})) // 3
    fmt.Println(minOperations1([]int{1,5,2,4,1})) // 14
    fmt.Println(minOperations1([]int{8})) // 0
}