제출 #736547

#	제출 시각	아이디	문제	언어	결과	실행 시간	메모리
736547		rahulverma	Network (BOI15_net)	Java	0 / 100	163 ms	11448 KiB

net

import java.io.*;
import java.util.*;

public class net {

	public static void main(String[] args) {
		Scanner s = new Scanner(System.in);
		int n = s.nextInt();
		ArrayList<ArrayList<Integer>> graph = new ArrayList<>();
		for(int i = 0; i < n; i++) graph.add(new ArrayList<Integer>());
		for(int i = 1; i < n; i++) {
			int v1 = s.nextInt() - 1;
			int v2 = s.nextInt() - 1;
			graph.get(v1).add(v2);
			graph.get(v2).add(v1);
		}
		boolean found = true;
		ArrayList<Integer> ans = new ArrayList<Integer>();
		for(int i = 0; i < n; i++) {
			if(graph.get(i).size() == 1) {
				ans.add(i+1);
				if(i == 0) found = true;
			}
		}
		if(found) ans.add(1);
		Collections.sort(ans, Collections.reverseOrder());
		System.out.println((int) ans.size()/2);
		for(int i = 0; i < ans.size()/2; i += 1) {
			System.out.println(ans.get(2*i) + " " + ans.get(2*i + 1));
		}
	}

}

• Subtask 1: 0 / 18
• Subtask 2: 0 / 45
• Subtask 3: 0 / 37