2025-08-02 11:10:21 +0000 UTC

class Solution:
    def numEquivDominoPairs(self, dominoes: List[List[int]]) -> int:
        freqs = [0] * 100
        res = 0
        for num1, num2 in dominoes:
            if num1 > num2:
                val = num1 * 10 + num2
            else:
                val = num2 * 10 + num1
            res += freqs[val]
            freqs[val] += 1
        return res