探险营地

/*
 * 思路：
 * 1. 用一个Set存储初始已知的营地。
 * 2. 遍历每次探险记录，计算每次新发现的营地数量。
 * 3. 找出新发现营地最多且索引最小的那次探险。
 * 4. 使用Java Stream进行操作。
 */
import java.util.*;
import java.util.stream.Collectors;
import java.util.stream.Stream;

public class ExpeditionSolutionStream {
    public static int findExpeditionWithMostNewCamps(String[] expeditions) {
        if (expeditions.length == 0) return -1;
        Set<String> knownCamps = Arrays.stream(expeditions[0].split("->")).collect(Collectors.toSet());

        int[] maxNewCamps = {0};
        int[] resultIndex = {-1};

        for (int i = 1; i < expeditions.length; i++) {
            Set<String> newCamps = Arrays.stream(expeditions[i].split("->"))
                                         .filter(camp -> !camp.isEmpty() && !knownCamps.contains(camp))
                                         .collect(Collectors.toSet());

            if (newCamps.size() > maxNewCamps[0]) {
                maxNewCamps[0] = newCamps.size();
                resultIndex[0] = i;
            }
            knownCamps.addAll(newCamps);
        }
        return resultIndex[0];
    }

    public static void main(String[] args) {
        String[] expeditions = {"leet->code","leet->code->Campsite->Leet","leet->code->leet->courier"};
        System.out.println(findExpeditionWithMostNewCamps(expeditions)); // 输出 1
    }
}