poj3278 Catch That Cow |bfs|队列|Java

http://poj.org/problem?id=3278

import java.sql.Time;
import java.util.Arrays;
import java.util.LinkedList;
import java.util.Queue;
import java.util.Scanner;

public class Main{

	public static int k, n;
	public static int MAXN = 100000;
	public static int[] vis = new int[100005];

	public static class P {
		int p;
		int time;

		P(int x, int y) {
			p = x;
			time = y;
		}
	}

	public static void bfs() {
		return;
	}

	public static void main(String[] args) {
		Scanner scanner = new Scanner(System.in);
		while (scanner.hasNext()) {
			Arrays.fill(vis, 0);
			
			n = scanner.nextInt();
			k = scanner.nextInt();

			P p = new P(n, 0);
			Queue
 q = new LinkedList
();
			q.offer(p);
			vis[n] = 1;
			while (!q.isEmpty()) {
				P t = q.poll();
				if (t.p == k) {
					System.out.println(t.time);
					break;
				} else {
					if (t.p - 1 >= 0 && vis[t.p - 1] != 1) {
						q.offer(new P(t.p - 1, t.time + 1));
						vis[t.p - 1] = 1;
					}
					if (t.p + 1 <= MAXN && vis[t.p + 1] != 1) {
						q.offer(new P(t.p + 1, t.time + 1));
						vis[t.p + 1] = 1;
					}
					if (t.p * 2 <= MAXN && vis[t.p*2] != 1) {
						q.offer(new P(t.p * 2, t.time + 1));
						vis[t.p * 2] = 1;
					}
					//System.out.print(t.p*2+"=");
					//System.out.println(t.time);
				}
			}
		}
		return;
	}
}