Minimum operations to make array equal ii

Array Math Greedy

33.0% acceptance

Feb 25, 2026

442

You are given two integer arrays nums1 and nums2 of equal length n and an integer k. You can perform the following operation on nums1: Choose two indexes i and j and increment nums1[i] by k and decrement nums1[j] by k. nums1 is said to be equal to nums2 if for all indices i such that 0 <= i < n, nums1[i] == nums2[i]. Return the minimum number of operations required to make nums1 equal to nums2. If it is impossible to make them equal, return -1.

Solution

Rust

Time O(n)

Space O(1)

LeetCode

solution.rs

impl Solution {
  pub fn min_operations(nums1: Vec<i32>, nums2: Vec<i32>, k: i32) -> i64 {
    if k == 0 {
      return if nums1 == nums2 { 0 } else { -1 };
    }
    let mut pos_sum = 0i64;
    let mut neg_sum = 0i64;
    for (&a, &b) in nums1.iter().zip(nums2.iter()) {
      let diff = (b - a) as i64;
      if diff % k as i64 != 0 {
        return -1;
      }
      let d = diff / k as i64;
      if d > 0 {
        pos_sum += d;
      } else {
        neg_sum += -d;
      }
    }
    if pos_sum != neg_sum {
      return -1;
    }
    pos_sum
  }
}