Leetcode 2225. Find Players With Zero or One Losses

2225. Find Players With Zero or One Losses

アプローチ

Hashmap

class Solution {
    public List<List<Integer>> findWinners(int[][] matches) {
        
        HashMap<Integer, Integer> t1 = new HashMap<>();
        HashMap<Integer, Integer> t2 = new HashMap<>();

        for (int i = 0; i < matches.length; i++) {
            t1.put(matches[i][0], t1.getOrDefault(matches[i][0], 0) + 1);
        }

        for (int i = 0; i < matches.length; i++) {
            t2.put(matches[i][1], t2.getOrDefault(matches[i][1], 0) + 1);
        }

        List<Integer> r1 = t1.entrySet().stream().filter(obj -> t2.containsKey(obj.getKey()) == false).map(Map.Entry::getKey).collect(Collectors.toList());
        List<Integer> r2 = t2.entrySet().stream().filter(obj -> obj.getValue() == 1).map(Map.Entry::getKey).collect(Collectors.toList());
        List<List<Integer>> result = new ArrayList<>();
        Collections.sort(r1);
        Collections.sort(r2);

        result.add(r1);
        result.add(r2);

        return result;
    }
}