题目标签：HashMap
题目给了我们两个句子，让我们找出不常见单词，只出现过一次的单词就是不常见单词。
把A 和 B 里的word 都存入 map，记录它们出现的次数。之后遍历map，把只出现过一次的存入 result。
Java Solution:
Runtime: 3 ms, faster than 89.90%
Memory Usage: 37.2 MB, less than 85.88%
完成日期：03/27/2019
关键点：hashmap
class Solution { public String[] uncommonFromSentences(String A, String B) { Map<String, Integer> map = new HashMap<>(); List<String> result = new ArrayList<>(); // put each work into map for(String str : (A + " " + B).split(" ")) { map.put(str, map.getOrDefault(str, 0) + 1); } // iterate map to put all the word with value 1 into arraylist for(String str : map.keySet()) { if(map.get(str) == 1) result.add(str); } return result.toArray(new String[0]); } }
参考资料：https://leetcode.com/problems/uncommon-words-from-two-sentences/discuss/?currentPage=1&orderBy=recent_activity&query=
LeetCode 题目列表 - LeetCode Questions List
题目来源：https://leetcode.com/
LeetCode 884. Uncommon Words from Two Sentences (两句话中的不常见单词)
原文：https://www.cnblogs.com/jimmycheng/p/10787673.html