Решение

class Solution {
    fun numIdenticalPairs(nums: IntArray): Int {
        val freq = mutableMapOf<Int, Int>()
        var count = 0
        for (num in nums) {
            count += freq.getOrDefault(num, 0)
            freq[num] = freq.getOrDefault(num, 0) + 1
        }
        return count
    }
}