884. Uncommon Words from Two Sentences

题目

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

A word is uncommonif 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.

解题思路

见程序注释