English:

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.

中文：

給定兩個(gè)句子 A 和 B 诱建。 （句子是一串由空格分隔的單詞桂肌。每個(gè)單詞僅由小寫字母組成。）
如果一個(gè)單詞在其中一個(gè)句子中只出現(xiàn)一次瞎饲，在另一個(gè)句子中卻沒有出現(xiàn)姿鸿，那么這個(gè)單詞就是不常見的。
返回所有不常用單詞的列表。
您可以按任何順序返回列表填帽。
示例 1：
輸入：A = "this apple is sweet", B = "this apple is sour"
輸出：["sweet","sour"]
示例 2：
輸入：A = "apple apple", B = "banana"
輸出：["banana"]
提示：
0 <= A.length <= 200
0 <= B.length <= 200
A 和 B 都只包含空格和小寫字母。

1.

開始我是將兩句分開來處理咙好。明顯顯得很擁擠篡腌，代碼有點(diǎn)啰嗦。

class Solution(object):
    def uncommonFromSentences(self, A, B):
        """
        :type A: str
        :type B: str
        :rtype: List[str]
        """        
        word_a = A.split(' ')
        d_a = {k:0 for k in word_a}
        word_b = B.split(' ')
        d_b = {k:0 for k in word_b}
        for x in word_a:
            d_a[x] += 1
        for y in word_b:
            d_b[y] += 1
        for k in d_a.keys():
            if d_a[k]==1:
                if k not in result and k not in d_b:
                    result.append(k)
        for k in d_b.keys():
            if d_b[k]==1:
                if k not in result and k not in d_a:
                    result.append(k)
        return result

理解還是很好理解的勾效，后面我就把兩個(gè)句子放到一起去處理了嘹悼。

這是分開處理的

2.

我把兩個(gè)句子加到一起，然后在處理层宫，但是后面發(fā)現(xiàn)變慢了杨伙。。萌腿。限匣。。

class Solution(object):
    def uncommonFromSentences(self, A, B):
        """
        :type A: str
        :type B: str
        :rtype: List[str]
        """
        st = A+' '+ B
        a = st.split(' ')
        s = {k:0 for k in st.split(' ')}
        result = []
        for l in a:
            s[l] += 1
        for i in a:
            if s[i]==1:
                if i not in result:
                    result.append(i)
        return result

image.png

我覺得是因?yàn)樵诤喜⒄Z句時(shí)的原因毁菱，因?yàn)?對(duì)兩個(gè)字符串使用膛腐，會(huì)新創(chuàng)建新的字符串實(shí)例，所以會(huì)慢鼎俘，而且內(nèi)存變大。