Create number-of-good-pairs.py

Author: kamyu104

Python/number-of-good-pairs.py

@@ -0,0 +1,13 @@
+# Time:  O(n)
+# Space: O(n)
+
+import collections
+
+
+class Solution(object):
+    def numIdenticalPairs(self, nums):
+        """
+        :type nums: List[int]
+        :rtype: int
+        """
+        return sum(c*(c-1)//2 for c in collections.Counter(nums).itervalues())