[백준] 1717 집합의 표현 - Data Structure / Java

• 문제 링크

1717번: 집합의 표현

 

• 풀이 과정

 

• 풀이 코드

import java.io.BufferedReader;
import java.io.BufferedWriter;
import java.io.IOException;
import java.io.InputStreamReader;
import java.io.OutputStreamWriter;
import java.util.StringTokenizer;

public class Main {

    static int[] parent;

    public static void main(String[] args) throws IOException {
        BufferedReader br = new BufferedReader(new InputStreamReader(System.in));
        BufferedWriter bw = new BufferedWriter(new OutputStreamWriter(System.out));
        StringTokenizer st = new StringTokenizer(br.readLine());

        int n = Integer.parseInt(st.nextToken());
        int m = Integer.parseInt(st.nextToken());

        parent = new int[n + 1];
        for (int i = 1; i <= n; i++)
            parent[i] = i;

        for (int i = 0; i < m; i++) {
            st = new StringTokenizer(br.readLine());
            int comm = Integer.parseInt(st.nextToken());
            int a = Integer.parseInt(st.nextToken());
            int b = Integer.parseInt(st.nextToken());

            if (comm == 0)
                union(a, b);
            else
                bw.write((find(a) == find(b) ? "YES" : "NO") + "\n");
        }

        bw.flush();
    }

    private static int find(int node) {
        if (parent[node] == node)
            return node;

        return parent[node] = find(parent[node]);
    }

    private static void union(int a, int b) {
        int aRoot = find(a);
        int bRoot = find(b);

        parent[bRoot] = aRoot;
    }

}