LeetCode 884. Uncommon Words from Two Sentences (两句话中的不常见单词)

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=

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