2206.js

/** ------------------------------------------------------------------------------
 * 
 * 2206. Divide Array Into Equal Pairs
 * Topics: Array, Hash Table
 * https://leetcode.com/problems/divide-array-into-equal-pairs/description/?envType=daily-question&envId=2025-03-17
 * 
 ------------------------------------------------------------------------------ */
/**
 * @param {number[]} nums
 * @return {boolean}
 */
const divideArray = function (nums) {
  const hash = {}

  for (let n of nums) {
    hash[n] = (hash[n] || 0) + 1
  }

  for (const key in hash) {
    if (hash[key] % 2 !== 0) {
      return false
    }
  }

  return true
}

console.log(divideArray([3, 2, 3, 2, 2, 2]))