leetcode/work/Default/Easy/Array/1636.sort-array-by-increasing-frequency.js

/*
 * 1636. Sort Array by Increasing Frequency
 * Difficulty: Easy
 * https://leetcode.com/problems/sort-array-by-increasing-frequency/
 *
 * ──────────────────────────────────────────────────
 *
 * Given an array of integers nums, sort the array in increasing order
 * based on the frequency of the values. If multiple values have the same
 * frequency, sort them in decreasing order.
 *
 * Return the sorted array.
 *
 *
 *
 * Example 1:
 *
 * Input: nums = [1,1,2,2,2,3]
 * Output: [3,1,1,2,2,2]
 * Explanation: '3' has a frequency of 1, '1' has a frequency of 2, and
 * '2' has a frequency of 3.
 *
 * Example 2:
 *
 * Input: nums = [2,3,1,3,2]
 * Output: [1,3,3,2,2]
 * Explanation: '2' and '3' both have a frequency of 2, so they are
 * sorted in decreasing order.
 *
 * Example 3:
 *
 * Input: nums = [-1,1,-6,4,5,-6,1,4,1]
 * Output: [5,-1,4,4,-6,-6,1,1,1]
 *
 *
 *
 * Constraints:
 *
 * 	• 1 <= nums.length <= 100
 *
 * 	• -100 <= nums[i] <= 100
 */

/**
 * @param {number[]} nums
 * @return {number[]}
 */
var frequencySort = function (nums) {
  const freq = {};
  for (let n of nums) freq[n] = (freq[n] || 0) + 1;
  return nums.sort((a, b) => freq[a] - freq[b] || b - a);
};