近义词句子

/*
题目思路：
1. 使用stream API简化操作。
2. 定义一个方法来生成近义词句子。
3. 使用递归或回溯方法来生成所有可能的句子组合。
4. 对每个单词，替换成它的近义词，并生成新的句子。
5. 最终返回所有可能的句子。
*/
import java.util.*;
import java.util.stream.Collectors;

public class SynonymousSentencesStream {
    public List<String> generateSentences(List<List<String>> synonyms, String text) {
        Map<String, List<String>> map = new HashMap<>();
        for (List<String> pair : synonyms) {
            map.putIfAbsent(pair.get(0), new ArrayList<>());
            map.putIfAbsent(pair.get(1), new ArrayList<>());
            map.get(pair.get(0)).add(pair.get(1));
            map.get(pair.get(1)).add(pair.get(0));
        }
        String[] words = text.split(" ");
        List<String> result = new ArrayList<>();
        generate(words, 0, map, new StringBuilder(), result);
        return result;
    }

    private void generate(String[] words, int index, Map<String, List<String>> map, StringBuilder sb, List<String> result) {
        if (index == words.length) {
            result.add(sb.toString().trim());
            return;
        }
        String word = words[index];
        List<String> synonyms = map.getOrDefault(word, Arrays.asList(word));
        synonyms.stream().forEach(synonym -> {
            int len = sb.length();
            sb.append(synonym).append(" ");
            generate(words, index + 1, map, sb, result);
            sb.setLength(len);
        });
    }

    public static void main(String[] args) {
        SynonymousSentencesStream ss = new SynonymousSentencesStream();
        List<List<String>> synonyms = Arrays.asList(Arrays.asList("happy", "joyful"), Arrays.asList("sad", "sorrow"));
        String text = "I am happy today but was sad yesterday";
        List<String> sentences = ss.generateSentences(synonyms, text);
        sentences.forEach(System.out::println);
    }
}