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] <= 104

SOLUTION:

class Solution:
    def minOperations(self, nums: List[int]) -> int:
        n = len(nums)
        ctr = 0
        for i in range(n - 1):
            if nums[i + 1] <= nums[i]:
                ctr += nums[i] + 1 - nums[i + 1]
                nums[i + 1] = nums[i] + 1
        return ctr