Create number-of-equivalent-domino-pairs.py

Author: kamyu104

Python/number-of-equivalent-domino-pairs.py

@@ -0,0 +1,14 @@
+# Time:  O(n)
+# Space: O(n)
+
+import collections
+
+
+class Solution(object):
+    def numEquivDominoPairs(self, dominoes):
+        """
+        :type dominoes: List[List[int]]
+        :rtype: int
+        """
+        counter = collections.Counter((min(x), max(x)) for x in dominoes)
+        return sum(v*(v-1)//2 for v in counter.itervalues())