Minimum number of increments on subarrays to form a target array

Array Dynamic Programming Stack Greedy Monotonic Stack

78.1% acceptance

Feb 25, 2026

2132

108

You are given an integer array target. You have an integer array initial of the same size as target with all elements initially zeros. In one operation you can choose any subarray from initial and increment each value by one. Return the minimum number of operations to form a target array from initial.

Solution

Rust

Time O(1)

Space O(1)

LeetCode

solution.rs

impl Solution {
  pub fn min_number_operations(target: Vec<i32>) -> i32 {
    // Answer = sum of max(0, target[i] - target[i-1]) where target[-1] = 0
    target[0] + target.windows(2)
      .map(|w| (w[1] - w[0]).max(0))
      .sum::<i32>()
  }
}