# https://leetcode.com/problems/number-of-equivalent-domino-pairs

from typing import Dict, List, Tuple

class Solution:
    def numEquivDominoPairs(self, dominoes: List[List[int]]) -> int:
        m: Dict[Tuple[int, int], int] = {}
        result = 0
        for [v1, v2] in dominoes:
            t = (v1, v2)
            if v2 > v1:
                t = (v2, v1)
            if t in m:
                result += m[t]
            m[t] = m.get(t, 0) + 1
        return result