题目描述:
方法一:
class Solution(object): def numEquivDominoPairs(self, dominoes): """ :type dominoes: List[List[int]] :rtype: int """ f = {} ret = 0 for d in dominoes: if d[0] > d[1]: d[0], d[1] = d[1], d[0] x = d[0] * 10 + d[1] ret += f.get(x, 0) f[x] = f.get(x, 0) + 1 return ret
另:
class Solution: def numEquivDominoPairs(self, dominoes: List[List[int]]) -> int: hashmap = collections.defaultdict(int) for i, j in dominoes: if i > j: i, j = j, i hashmap[(i,j)] += 1 ans = 0 for key in hashmap: ans += hashmap[key]*(hashmap[key]-1)//2 return an