2342.js

/** ------------------------------------------------------------------------------
 * 
 * 2342. Max Sum of a Pair With Equal Sum of Digits
 * Topics: Hash Map
 * https://leetcode.com/problems/max-sum-of-a-pair-with-equal-sum-of-digits/?envType=daily-question&envId=2025-02-12
 * 
 ------------------------------------------------------------------------------ */
/**
 * @param {number[]} nums
 * @return {number}
 */
var maximumSum = function (nums) {
  const map = new Map()
  let max = -1

  const getSum = (num) => {
    return num
      .toString()
      .split("")
      .reduce((acc, cur) => acc + Number(cur), 0)
  }

  /**
   * getSum 함수의 시간복잡도를 약간 더 개선한다면
   */
  // function getSum(num) {
  //   let sum = 0;
  //   while (num > 0) {
  //     sum += num % 10;
  //     num = Math.floor(num / 10);
  //   }

  //   return sum;
  // }

  for (let num of nums) {
    let sum = getSum(num)

    if (map.has(sum)) {
      max = Math.max(max, num + map.get(sum))
      map.set(sum, Math.max(map.get(sum), num))
    } else {
      map.set(sum, num)
    }
  }
  return max
}

console.log(maximumSum([18, 43, 36, 13, 7]))