HDU2717-Catch That Cow

标签：bfs   算法   数据结构   

If the cow, unaware of its pursuit, does not move at all, how long does it take for Farmer John to retrieve it?

import java.util.*;
public class Main {
	public LinkedList<Node> queue;
	public boolean []visit;
	public Main(){
		this.queue=new LinkedList<Main.Node>();
		visit=new boolean[200000];
	}
	public class Node{
		int num;
		int count;
		public Node(){}
		public Node(int num,int count) {
			this.num=num;
			this.count=count;
		}
	}
	public int bfs(int n,int k){
		if(n==k) return 0; 
		Node n0=new Node(n,0);
		
		queue.add(n0);
		visit[n]=true;
		
		while(!queue.isEmpty()){
			Node tmp=queue.peek();
			if(tmp.num==k) return tmp.count; 
			queue.remove();
			Node n1=new Node(tmp.num-1,tmp.count+1);
			Node n2=new Node(tmp.num+1,tmp.count+1);
			Node n3=new Node(tmp.num*2,tmp.count+1);
			if(n1.num==k) return n1.count;
			if(n2.num==k) return n2.count; 
			if(n3.num==k) return n3.count; 
			if(n1.num<150005 && n1.num>=0 && visit[n1.num]!=true ){
				queue.add(n1);
				visit[n1.num]=true;
			}
			if(n2.num<150005 && n2.num>=0 && visit[n2.num]!=true) {
				queue.add(n2);
				visit[n2.num]=true;
			}
			if(n3.num<150005 && n3.num>=0 && visit[n3.num]!=true){
				queue.add(n3);
				visit[n3.num]=true;
			}
		}
		return 0;
	}
	public static void main(String[] args) {
		int n,k;
		Scanner cin=new Scanner(System.in);
		while(cin.hasNext()){
			n=cin.nextInt();
			k=cin.nextInt();
			System.out.println(new Main().bfs(n, k));
		}
	}

}

HDU2717-Catch That Cow,布布扣,bubuko.com

HDU2717-Catch That Cow

标签：bfs   算法   数据结构   

原文地址：http://blog.csdn.net/dutsoft/article/details/27663821