多校 Robot Motion

题目链接：http://acm.hust.edu.cn/vjudge/contest/124435#problem/J

密码：acm

Sample Input
3 6 5
NEESWE
WWWESS
SNWWWW
4 5 1
SESWE
EESNW
NWEEN
EWSEN
0 0 0
Sample Output
10 step(s) to exit
3 step(s) before a loop of 8 step(s)

分析：

#include <iostream>
#include <stdio.h>
#include <string.h>
#include <algorithm>
#include <stdlib.h>
#include<queue>
#include<math.h>
using namespace std;

#define N 1001
char s[N][N];
int a[N][N],b[N][N];

int main()
{
    int n,m,c,ans;
    while(scanf("%d%d%d",&n,&m,&c),n+m+c)
    {
        memset(a,0,sizeof(a));
        memset(b,0,sizeof(b));
        ans=0;

        for(int i=1;i<=n;i++)
            scanf("%s",s[i]);

       int i=1;
       int j=c-1;///字符串里面从零开始记录的，老是忘~~~~(>_<)~~~~ 
        while(1)
        {
            b[i][j]=1;
            if(s[i][j]=='N')
                i=i-1;
            else if(s[i][j]=='S')
                i=i+1;
            else if(s[i][j]=='E')
                j=j+1;
            else
                j=j-1;
            ans++;
            if(b[i][j])
            {
                printf("%d step(s) before a loop of %d step(s)
",a[i][j],ans-a[i][j]);
                break;
            }
            a[i][j]=ans;

            if(i==0||j==-1||i==n+1||j==m)
            {
                printf("%d step(s) to exit
",ans);
                break;
            }
        }
    }
    return 0;
}