标签：bfs   模板   

原题http://acm.hdu.edu.cn/showproblem.php?pid=1548

A strange lift

Time Limit: 2000/1000 MS (Java/Others)    Memory Limit: 65536/32768 K (Java/Others)
Total Submission(s): 11907    Accepted Submission(s): 4530

5 1 5
3 3 1 2 5
0

3

//BFS判断的时候要注意。

#include <stdio.h>
#include <stdlib.h>
#include <malloc.h>
#include <limits.h>
#include <ctype.h>
#include <string.h>
#include <string>
#include <math.h>
#include <algorithm>
#include <iostream>
#include <queue>
#include <vector>
#include <deque>
#include <set>
#include <map>
using namespace std;
#define MAXN 200 + 10

struct node{
    //int vis;
    int step;
    int floor;
    //int fsum;
};
int vis[MAXN];
int sum[MAXN];
int n,A,B;
//queue<node>q;
void BFS(){
    //int i;
    int mark1,mark2;
    int flag = 0;
    //queue<node> q;
    node front,rear1,rear2;
    queue<node> q;
    front.step = 0;
    front.floor = A;
    //front.fsum = sum[A];
    vis[A] = 1;
    q.push(front);
    while(!q.empty()){
        front = q.front();
        q.pop();
        
        if(front.floor == B){
            flag = 1;
            printf("%d\n",front.step);
            break;
        }
        mark1 = front.floor+sum[front.floor];
        mark2 = front.floor-sum[front.floor];
        if((mark1>=1&&mark1<=n) && (vis[mark1]==0)){
            rear1.floor = mark1;
            vis[mark1] = 1;
            //rear1.vis = 1;
            //rear1.fsum = sum[mark1];
            rear1.step = front.step+1;
            q.push(rear1);
        }
        //mark = front.floor - front.sum;
        if((mark2>=1&&mark2<=n) && (vis[mark2]==0)){
            rear2.floor = mark2;
            //rear2.vis = 1;
            vis[mark2] = 1;
            //rear2.fsum = sum[mark2];
            rear2.step = front.step+1;
            q.push(rear2);
        }
    }
    if(flag == 0){
        printf("-1\n");
    }
}

int main(){
    int i;

    while(~scanf("%d",&n)){
        if(n == 0){
            break;
        }
        scanf("%d%d",&A,&B);
        //memset(a,0,sizeof(a));
		memset(vis,0,sizeof(vis));
		memset(sum,0,sizeof(sum));
        
        for(i=1;i<=n;i++){
            scanf("%d",&sum[i]);
        }


        BFS();

       
    }

    return 0;
}

BFS

标签：bfs   模板   

原文地址：http://blog.csdn.net/zcr_7/article/details/39002529