1534. Count Good Triplets

// Approach: Brute-force O(n³) check all triplets i<j<k satisfying all three difference constraints.
// Time: O(n³) Space: O(1)

public class Solution
{
    public int CountGoodTriplets(int[] arr, int a, int b, int c)
    {
        int ans = 0;

        for (int i = 0; i < arr.Length; ++i)
        {
            for (int j = i + 1; j < arr.Length; ++j)
            {
                for (int k = j + 1; k < arr.Length; ++k)
                {
                    if (Math.Abs(arr[i] - arr[j]) <= a &&
                        Math.Abs(arr[j] - arr[k]) <= b &&
                        Math.Abs(arr[i] - arr[k]) <= c)
                        ++ans;
                }
            }
        }

        return ans;
    }
}