프로그래머스 - (2019 카카오 개발자 겨울 인턴십) 튜플 (Java)

programmers.co.kr/learn/courses/30/lessons/64065

코딩테스트 연습 - 튜플

import java.util.ArrayList;
import java.util.Arrays;
import java.util.Comparator;
import java.util.HashSet;
import java.util.regex.Matcher;
import java.util.regex.Pattern;
import java.util.stream.Collectors;

class Solution {
    public int[] solution(String s) {
        ArrayList<Integer> answer = new ArrayList<>();
        ArrayList<HashSet<Integer>> sets = new ArrayList<>();

        Pattern pattern = Pattern.compile("\\{[\\d,]+\\}");
        Matcher matcher = pattern.matcher(s);
        while (matcher.find()){
            String found = matcher.group();
            found = found.replaceAll("[\\{\\}]", "");
            String[] numsStr = found.split(",");
            HashSet<Integer> set
                = (HashSet<Integer>) Arrays.stream(numsStr).mapToInt(Integer::parseInt)
                .boxed().collect(Collectors.toSet());
            sets.add(set);
        }

        sets.sort(new Comparator<HashSet<Integer>>() {
            @Override
            public int compare(HashSet<Integer> o1, HashSet<Integer> o2) {
                return Integer.compare(o1.size(), o2.size());
            }
        });

        answer.addAll(sets.get(0));

        for (int i = 1; i < sets.size(); i++){
            sets.get(i).removeAll(sets.get(i - 1));
            answer.addAll(sets.get(i));
            sets.get(i).addAll(answer);
        }

        return answer.stream().mapToInt(Integer::intValue).toArray();
    }
}