两句话中的不常见单词

/*
 * 思路：
 * 1. 将两个句子拆分成单词数组。
 * 2. 使用流处理将两个数组合并，并计算每个单词的出现次数。
 * 3. 过滤出只出现一次的单词。
 */
import java.util.*;
import java.util.stream.Collectors;
import java.util.stream.Stream;

public class UncommonWordsStream {
    public static List<String> uncommonFromSentences(String s1, String s2) {
        // 将句子拆分成单词数组，并合并两个数组
        String[] words1 = s1.split(" ");
        String[] words2 = s2.split(" ");
        
        // 使用流处理计算单词出现次数
        Map<String, Long> countMap = Stream.concat(Arrays.stream(words1), Arrays.stream(words2))
                .collect(Collectors.groupingBy(word -> word, Collectors.counting()));
        
        // 过滤出只出现一次的单词
        return countMap.entrySet().stream()
                .filter(entry -> entry.getValue() == 1)
                .map(Map.Entry::getKey)
                .collect(Collectors.toList());
    }

    public static void main(String[] args) {
        String s1 = "this apple is sweet";
        String s2 = "this apple is sour";
        System.out.println(uncommonFromSentences(s1, s2));
    }
}