Minimum operations to make the array increasing

Array Greedy

81.9% acceptance

Feb 25, 2026

1317

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. 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.

Solution

Rust

Time O(n)

Space O(1)

LeetCode

solution.rs

impl Solution {
  pub fn min_operations(nums: Vec<i32>) -> i32 {
    let mut ops = 0i32;
    let mut prev = nums[0];
    for i in 1..nums.len() {
      let needed = prev + 1;
      if nums[i] < needed {
        ops += needed - nums[i];
        prev = needed;
      } else {
        prev = nums[i];
      }
    }
    ops
  }
}