Leetcode Solution - 1512. Number of Good Pairs

NumIdenticalPairs.cs

public class Solution {
    public int NumIdenticalPairs(int[] nums) {
        var sum = 0;
        var arr = new int[101];
        foreach (var num in nums) sum += arr[num]++;
        return sum;
    }
}

// Result: https://leetcode.com/submissions/detail/570762775/

NumIdenticalPairs2.cs

public class Solution {
    public int NumIdenticalPairs(int[] nums) {
        var sum = 0;
        var dic = new Dictionary<int, int>();
        foreach (var num in nums) sum += !dic.TryAdd(num, 1) ? dic[num]++ : 0;
        return sum;
    }
}

// Result: https://leetcode.com/submissions/detail/570760030/