Решение

class Solution {
    fun frequencySort(nums: IntArray): IntArray {
        val freq = IntArray(201)
        var i = 0
        while (i < nums.size) {
            freq[nums[i] + 100]++
            i++
        }
        val res = IntArray(nums.size)
        var idx = 0
        val n = nums.size
        var f = 1
        while (f <= n) {
            var v = 100
            while (v >= -100) {
                if (freq[v + 100] == f) {
                    var k = 0
                    while (k < f) {
                        res[idx++] = v
                        k++
                    }
                }
                v--
            }
            f++
        }
        return res
    }
}