pku 1573 Robot Motion（水题）

#include <stdio.h>
#include <ctype.h>
#include <string.h>
#include <stdlib.h>

 

#define MAXN 15
#define MAXM 15

//const int dir[4][2] = { {0, 1}, {1, 0}, {0, -1}, {-1, 0} }; //east, south, west, north

char grid[MAXN][MAXM];
int step[MAXN][MAXM];

bool canExit(const int N, const int M, int i, int j)
{
    if(i < 0 || j < 0 || i >= N || j >= M)
        return true;
    else
        return false;
}

void solve(const int N, const int M, const int S)
{
    memset(step, 0, sizeof(step));

    int i, j;
    for(i = 0; i < N; i++)
    {
        scanf("%s", grid[i]);
    }
    i = 0;
    j = S;
    int st = 0;
    step[i][j] = ++st;

    while(1)
    {
        switch(grid[i][j])
        {
            case 'E':
                j++;
                break;
            case 'S':
                i++;
                break;
            case 'W':
                j--;
                break;
            case 'N':
                i--;
                break;
            default:
                break;
        }
        if(canExit(N, M, i, j))
        {//10 step(s) to exit
          //  if(st > 1) printf("%d steps to exit\n", st); //WA，那句话干啥的，靠
          //  else printf("%d step to exit\n", st);
            printf("%d step(s) to exit\n", st);
            return;
        }
        else if(step[i][j] != 0)
        {//3 step(s) before a loop of 8 step(s)
            int x = step[i][j] - 1;
            int y = st - x;
          //  if(x > 1) printf("%d steps before a loop of %d steps\n", x, y);
          //  else printf("%d step before a loop of %d steps\n", x, y);
            printf("%d step(s) before a loop of %d step(s)\n", x, y);
            return;
        }
        else step[i][j] = ++st;
    }
}

int main()
{
    #ifndef ONLINE_JUDGE
    freopen("indata.txt", "r", stdin);
    #endif

    int n, m, s;
    while(scanf("%d %d %d", &n, &m, &s), n + m + s)
    {
        solve(n, m, s - 1);
    }
    return 0;
}