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LeetCode solutions

1227. Number of Equivalent Domino Pairs

My accepted Python solution to LeetCode problem 1227, Number of Equivalent Domino Pairs, running in 15ms.

  • Difficulty: Easy
  • Python
  • Runtime 15ms
  • Memory 23.7MB

Read the problem on LeetCode View on GitHub

The problem statement is LeetCode’s and stays on their site. What follows is my accepted solution.

Python

Accepted on LeetCode — runtime 15ms, memory 23.7MB, accepted 2025-12-30.

python
class Solution:
    def numEquivDominoPairs(self, dominoes: List[List[int]]) -> int:
        count = {}
        result = 0
        for a, b in dominoes:
            key = (min(a, b), max(a, b))
            if key in count:
                result += count[key]
                count[key] += 1
            else:
                count[key] = 1
        return result

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