题目地址

https://leetcode.cn/problems/find-players-with-zero-or-one-losses/description/

题目描述

代码及思路

class Solution {public List<List<Integer>> findWinners(int[][] matches) {//创建一个map记录比赛胜者组//创建一个map记录比赛败者组//全胜者不应该出现在败者组中//恰好只输了一场的在败者组中失败次数为1Map<Integer, Integer> winnerMap = new HashMap();Map<Integer, Integer> loserMap = new HashMap();for (int[] m : matches) {if (winnerMap.containsKey(m[0])) {winnerMap.put(m[0], winnerMap.get(m[0])+1);} else {winnerMap.put(m[0], 1);}if (loserMap.containsKey(m[1])) {loserMap.put(m[1], loserMap.get(m[1] )+1);} else {loserMap.put(m[1], 1);}}List<Integer> answers0List = winnerMap.keySet().stream().filter(e -> !loserMap.containsKey(e)).sorted().collect(Collectors.toList());List<Integer> answer1List = loserMap.entrySet().stream().filter(e->e.getValue()==1).map(e->e.getKey()).sorted().collect(Collectors.toList());List<List<Integer>> ans = new ArrayList<>();ans.add(answers0List);ans.add(answer1List);return ans;}
}