leetcode1128

 1 class Solution:
 2     def numEquivDominoPairs(self, dominoes: ‘List[List[int]]‘) -> int:
 3         n = len(dominoes)
 4         dic = dict()
 5         
 6         for do in dominoes:
 7             key = ()
 8             if do[0] <= do[1]:
 9                 key = (do[0],do[1])
10             else:
11                 key = (do[1],do[0])
12             if key in dic:
13                 dic[key] += 1
14             else:
15                 dic[key] = 1
16         pairs = 0
17         for k,v in dic.items():
18             if v == 1:
19                 pairs += 0
20             elif v == 2:
21                 pairs += 1
22             else:
23                 pairs += v * (v-1) // 2
24         return pairs