Number of Equivalent Domino Pairs

Given a list of dominoes, dominoes[i] = [a, b] is equivalent to dominoes[j] = [c, d] if and only if either (a == c and b == d), or (a == d and b == c) - that is, one domino can be rotated to be equal to another domino.

Return the number of pairs (i, j) for which 0 <= i < j < dominoes.length, and dominoes[i] is equivalent to dominoes[j].

LeetCode Problem - 1128

class Solution {
    public int numEquivDominoPairs(int[][] dominoes) {
        int count = 0; // Variable to store the number of equivalent domino pairs

        // Iterate through each domino pair
        for (int i = 0; i < dominoes.length; i++) {
            int a = dominoes[i][0]; // First number of the current domino
            int b = dominoes[i][1]; // Second number of the current domino

            // Check the rest of the dominoes after the current one
            for (int k = i + 1; k < dominoes.length; k++) {
                int c = dominoes[k][0]; // First number of the comparison domino
                int d = dominoes[k][1]; // Second number of the comparison domino

                // Check if the two dominoes are equivalent
                // Either (a, b) is the same as (c, d) or (a, b) is the same as (d, c)
                if ((a == c && b == d) || (a == d && b == c)) {
                    count++; // Increment the count if they are equivalent
                }
            }
        }
        return count; // Return the total number of equivalent domino pairs
    }
}