pku 1573 Robot Motion 第一周训练——模拟

http://poj.org/problem?id=1573

一个原来做过的模拟题，大早上做题就是头脑清楚啊。1Y..呵呵。。

#include <iostream>
#include <cstring>
#include <cstdio>
#define maxn 107
using namespace std;
char str[maxn][maxn];
bool visit[maxn][maxn];//标记是否已经走过
int map[maxn][maxn];//存储到达ij这点时走了多少步
int main()
{
    int n,m,s,i,j;
    int a,b;
    bool flag;
    while (cin>>n>>m>>s)
    {
        if (!n && !m && !s) break;
        memset(visit,false,sizeof(visit));
        flag = false;
        for (i = 0; i < n; ++i)
        scanf("%s",str[i]);
        i = 0; j = s - 1;
        int len = 1;
        map[i][j] = len++;
        visit[i][j] = true;
        while ((i >= 0 && i < n) && (j >=0 && j < m))
        {
            if (str[i][j] == 'N')
            {
                 i--;
                 if (visit[i][j] == true)
                 {
                     a = map[i][j] - 1;
                     b = map[i + 1][j] - map[i][j] + 1;
                     flag = true;
                     break;
                 }
                 visit[i][j] = true;
                 map[i][j] = len++;
            }
            else if (str[i][j] == 'S')
            {
                i++;
                if (visit[i][j] == true)
                 {
                     a = map[i][j] - 1;
                     b = map[i - 1][j] - map[i][j] + 1;
                     flag = true;
                     break;
                 }
                 visit[i][j] = true;
                 map[i][j] = len++;
            }
            else if (str[i][j] == 'W')
            {
                 j--;
                 if (visit[i][j] == true)
                 {
                     a = map[i][j] - 1;
                     b = map[i][j + 1] - map[i][j] + 1;
                     flag = true;
                     break;
                 }
                 visit[i][j] = true;
                 map[i][j] = len++;
            }
            else if (str[i][j] == 'E')
            {
                 j++;
                 if (visit[i][j] == true)
                 {
                     a = map[i][j] - 1;
                     b = map[i][j - 1] - map[i][j] + 1;
                     flag = true;
                     break;
                 }
                 visit[i][j] = true;
                 map[i][j] = len++;
            }
            a = i; b = j;
        }
        if (flag) printf("%d step(s) before a loop of %d step(s)\n",a,b);
        else      printf("%d step(s) to exit\n",map[a][b] - 1);
    }
    return 0;
}