[SWEA] 3289:서로소 집합 (Java 자바)

풀이 및 소스코드

 

union-find 사용하면 금방 해결할 수 있다.

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

public class Solution {
	static int[] p;
	static int n,m;
	public static void make() {
		for(int i=0;i<n;i++) {
			p[i] = i;
		}
	}
	
	public static int find(int a) {
		if(p[a] == a) {
			return a;
		}
		return p[a] = find(p[a]);
	}
	
	public static boolean union(int a, int b) {
		int p_a = find(a);
		int p_b = find(b);
		
		if(p_a==p_b) return false;
		
		if(p_a<=p_b) p[p_b] = p_a; //작은게 부모가 되도록 통일시켜주기위해 !
		else p[p_a] = p_b;
		return true;
	}
	
	public static void main(String[] args) throws IOException {
		BufferedReader br = new BufferedReader(new InputStreamReader(System.in));
		StringTokenizer st;
		StringBuilder sb = new StringBuilder();
		int t = Integer.parseInt(br.readLine());
		for(int tc=1;tc<=t;tc++) {
			st = new StringTokenizer(br.readLine());
			n = Integer.parseInt(st.nextToken());
			m = Integer.parseInt(st.nextToken());
			p = new int[n];
			sb.append("#").append(tc).append(" ");
			make();
			for(int i=0;i<m;i++) {
				st = new StringTokenizer(br.readLine());
				int c = Integer.parseInt(st.nextToken());
				int a = Integer.parseInt(st.nextToken())-1;
				int b = Integer.parseInt(st.nextToken())-1;
				//1부터 시작하므로 1씩 빼주깅
				if(c == 0) {
					union(a,b);
				}else {
					if(find(a)==find(b)) sb.append("1");
					else sb.append("0");
				}
			}
			sb.append("\n");
		}
		System.out.println(sb);
	}

}