Create count-common-words-with-one-occurrence.py

Author: kamyu104

Python/count-common-words-with-one-occurrence.py

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+# Time:  O(m + n)
+# Space: O(m + n)
+
+import collections
+
+
+class Solution(object):
+    def countWords(self, words1, words2):
+        """
+        :type words1: List[str]
+        :type words2: List[str]
+        :rtype: int
+        """
+        cnt = collections.Counter(words1)
+        for c in words2:
+            if cnt[c] < 2:
+                cnt[c] -= 1
+        return sum(v == 0 for v in cnt.itervalues())