[LeetCode] 884. Uncommon Words from Two Sentences_Easy tag: Hash Table

We are given two sentences A and B.  (A sentence is a string of space separated words.  Each word consists only of lowercase letters.)

A word is uncommon if it appears exactly once in one of the sentences, and does not appear in the other sentence.

Return a list of all uncommon words.

You may return the list in any order.

Example 1:

Input: A = "this apple is sweet", B = "this apple is sour"
Output: ["sweet","sour"]

Example 2:

Input: A = "apple apple", B = "banana"
Output: ["banana"]

Note:

1. 0 <= A.length <= 200
2. 0 <= B.length <= 200
3. A and B both contain only spaces and lowercase letters.

思路将所有words, 计数, == 1, append进入ans

Code

class Solution:
    def uncommonWord(self, A, B):
        words = A.split() +B.split()
        ans, d = [], collections.Counter(words)
        for k in d.keys():
            if d[k] == 1:
                ans.append(k)
        return ans