#2449 - Minimum Number of Operations to Make Arrays Similar

Hard • View on LeetCode • View on GitHub

Problem Description

You are given two positive integer arrays nums and target, of the same length.

In one operation, you can choose any two distinct indices i and j where 0 <= i, j < nums.length and:

set nums[i] = nums[i] + 2 and
set nums[j] = nums[j] - 2.

Two arrays are considered to be similar if the frequency of each element is the same.

Return the minimum number of operations required to make nums similar to target. The test cases are generated such that nums can always be similar to target.

Solution

/**
 * @param {number[]} nums
 * @param {number[]} target
 * @return {number}
 */
var makeSimilar = function(nums, target) {
  const evenNums = nums.filter(num => num % 2 === 0).sort((a, b) => a - b);
  const oddNums = nums.filter(num => num % 2 === 1).sort((a, b) => a - b);
  const evenTarget = target.filter(num => num % 2 === 0).sort((a, b) => a - b);
  const oddTarget = target.filter(num => num % 2 === 1).sort((a, b) => a - b);

  let result = 0;
  for (let i = 0; i < evenNums.length; i++) {
    if (evenNums[i] > evenTarget[i]) {
      result += (evenNums[i] - evenTarget[i]) / 2;
    }
  }

  for (let i = 0; i < oddNums.length; i++) {
    if (oddNums[i] > oddTarget[i]) {
      result += (oddNums[i] - oddTarget[i]) / 2;
    }
  }

  return result;
};