sgu398.java

SGU398题解

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

public class Solution implements Runnable {
	Scanner in = new Scanner(System.in);
	boolean[] used;
	int[][] link;
	int n, x;
	
	private void Init() {
		n = in.nextInt();
		link = new int[n][];
		x = in.nextInt();
		x--;
		int i, j, d;
		for (i = 0; i < n; i++) {
			d = in.nextInt();
			link[i] = new int[d];
			for (j = 0; j < d; j++) {
				link[i][j] = in.nextInt();
				link[i][j]--;
			}
		}
	}
	
	private void Work() {
		used = new boolean[n];
		Arrays.fill(used, false);
		int i, j, v;
		for (i = 0; i < link[x].length; i++) {
			v = link[x][i];
			for (j = 0; j < link[v].length; j++)
				used[link[v][j]] = true;
		}
		for (i = 0; i < link[x].length; i++)
			used[link[x][i]] = false;
		used[x] = false;
		int[] list = new int[n];
		int len = 0;
		for (i = 0; i < n; i++)
			if (used[i]) list[len++] = i + 1;
		System.out.println(len);
		for (i = 0; i < len; i++) {
			if (i > 0) System.out.print(" ");
			System.out.print(list[i]);
		}
		System.out.println();
	}
	
	public void run() {
		Init();
		Work();
	}
	
	public static void main(String args[]) {
		new Thread(new Solution()).start();
	}
}