1534: Count-Good-Triplets
Easy

I saw the restraints 3 <= arr.length <= 100 and realised they probably just wanted a simple brute-force solution.

Code:

class Solution {
public:
    int countGoodTriplets(vector<int>& arr, int a, int b, int c) {
        int ans = 0;
        for (int i = 0; i < arr.size(); ++i) {
            for (int j = i+1; j < arr.size(); ++j) {
                for (int k = j+1; k < arr.size(); ++k) {
                    if (abs(arr[i]-arr[j]) <= a && abs(arr[j]-arr[k]) <= b && abs(arr[i]-arr[k]) <= c) {
                        ++ans;
                    }
                }
            }
        }
        return ans;
    }
};

Complexity: