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1636. Sort Array by Increasing Frequency

EasyOpen on LeetCodeProblem statement

Problem Statement

1636. Sort Array by Increasing Frequency

Easy


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:

Java

Source file
class Solution {
    public int[] frequencySort(int[] nums) {
        int[] freq = new int[201];
        for(int n: nums)
            freq[n+100]++;
        Integer[] ans = Arrays.stream(nums).boxed().toArray(Integer[]::new);
        Arrays.sort(ans, (a, b) -> {
            if(freq[a+100]==freq[b+100])
                return b - a;
            return freq[a+100] - freq[b+100];
        });
        return Arrays.stream(ans).mapToInt(Integer::intValue).toArray();
    }
}