884.Uncommon Words from Two Sentences

Description

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.

题目链接：https://leetcode.com/problems/uncommon-words-from-two-sentences/description/

Difficulty: easy

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:

• 0 <= A.length <= 200
• 0 <= B.length <= 200
• 0 <= A[i] <= 10^9
• A and B both contain only spaces and lowercase letters.

分析

1. 如果有一项出现两次或以上，那么一定不是Uncommon Words；
2. 遍历A+B，定义一个set存储遍历结果，若该项已经存在于set中，说明出现不止一次，从list中移出。

参考代码

class Solution:
def uncommonFromSentences(self, A, B):
    d=set()
    li=[]
    a=A.split()+B.split()
    for index in a:
        if(index in d):
            if(index in li):
                li.remove(index)
        else:
            d.add(index)
            li.append(index)
    return li