前后拼接

/*
 * LeetCode 1181 - Before and After Puzzle
 * Given a list of phrases, we need to return the list of all combinations of phrases where the last word of the first phrase matches the first word of the second phrase.
 * The result should be sorted and duplicates should be removed.
 */
import java.util.*;
import java.util.stream.Collectors;
import java.util.stream.IntStream;

public class SolutionStream {
    public List<String> beforeAndAfterPuzzles(String[] phrases) {
        return IntStream.range(0, phrases.length)
            .boxed()
            .flatMap(i -> IntStream.range(0, phrases.length)
                .filter(j -> i != j)
                .filter(j -> phrases[i].split(" ")[phrases[i].split(" ").length - 1].equals(phrases[j].split(" ")[0]))
                .mapToObj(j -> phrases[i] + phrases[j].substring(phrases[j].split(" ")[0].length())))
            .collect(Collectors.toSet())
            .stream()
            .sorted()
            .collect(Collectors.toList());
    }
}