2022 KAKAO BLIND RECRUITMENT - 신고 결과 받기

    public static int[] solution(String[] id_list, String[] report, int k) {
        int[] answer = {};

        HashMap<String, Integer> id = new HashMap<>();
        HashMap<String, Integer> result = new HashMap<>();
        Set<String> reportList = new HashSet<>();

        // set이 중복 제거해주므로 신고자/신고당한자 담음
        for (String r : report) {
            reportList.add(r);
        }

        Iterator<String> iterator = reportList.iterator();
        while (iterator.hasNext()) {
            String str = iterator.next();
            String bad = str.split(" ")[1];

            id.put(bad, id.getOrDefault(bad, 0) + 1);
        }

        for (String s : reportList) {
            String reporter = s.split(" ")[0];
            String bad = s.split(" ")[1];

            if(id.get(bad)>=k) {
                result.put(reporter, result.getOrDefault(reporter, 0) + 1);
            }
        }

        answer = new int[id_list.length];
        int index  =0;
        for (String i : id_list) {
            answer[index] = (result.get(i)!=null) ? result.get(i) : 0;
            index++;
        }

        return answer;
    }