2085. Public string that has occurred once

topic：

Thought：

First useCountercount，use & The symbol is connected to two dictionarieskeys， The remaining part is both。
Traversing this remaining part，Determine whether it is equal to 1 Be

Code：

class Solution:
    def countWords(self, words1: List[str], words2: List[str]) -> int:
        words_1 = Counter(words1)
        words_2 = Counter(words2)
        ans = 0
        for i in words_1.keys() & words_2.keys():
            if words_1[i] == 1 and words_2[i] == 1:
                ans += 1
        return ans
     

One -line writing

return sum(1 for i in Counter(words1) & Counter(words2) if Counter(words1)[i] == 1 and Counter(words2)[i] == 1)