leet code - 1128. Number of Equivalent Domino Pairs(Easy, Hashing, Counting, Combinations)
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 dominoes[i] is equivalent to dominoes[j]. Example 1:Input: dominoes = [[1,2],[2,1],[3,4],[5,6]]Output: 1Example 2:Input: dominoes = [..
2025. 5. 5.