https://leetcode.com/problems/uncommon-words-from-two-sentences
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:
0 <= A.length <= 2000 <= B.length <= 200A and B both contain only spaces and lowercase letters.解题思路：
简单但是蛋疼的一道题目。读题目后发现，这里的uncommon，其实就是在A和B里面加起来只出现一次的。
先用map统计次数，然后拿出只出现一次的词，最后形成array。
class Solution { public String[] uncommonFromSentences(String A, String B) { Map<String, Integer> map = new HashMap<String, Integer>(); String[] a1 = A.split(" "); String[] b1 = B.split(" "); for (String str : a1) { map.put(str, map.getOrDefault(str, 0) + 1); } for (String str : b1) { map.put(str, map.getOrDefault(str, 0) + 1); } List<String> list = new ArrayList<String>(); for (Map.Entry<String, Integer> entry : map.entrySet()) { if (entry.getValue() == 1) { list.add(entry.getKey()); } } String[] res = new String[list.size()]; for (int i = 0; i < list.size(); i++) { res[i] = list.get(i); } return res; } }
有人写的更简洁，逻辑是一样的
https://leetcode.com/problems/uncommon-words-from-two-sentences/discuss/158967/C%2B%2BJavaPython-Easy-Solution-with-Explanation
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