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] <= 104`

1827. Minimum Operations to Make the Array Increasing
``````struct Solution;

impl Solution {
fn min_operations(mut nums: Vec<i32>) -> i32 {
let n = nums.len();
let mut res = 0;
for i in 1..n {
let target = nums[i - 1] + 1;
if nums[i] < target {
res += target - nums[i];
nums[i] = target;
}
}
res
}
}

#[test]
fn test() {
let nums = vec![1, 1, 1];
let res = 3;
assert_eq!(Solution::min_operations(nums), res);
let nums = vec![1, 5, 2, 4, 1];
let res = 14;
assert_eq!(Solution::min_operations(nums), res);
let nums = vec![8];
let res = 0;
assert_eq!(Solution::min_operations(nums), res);
}
``````