POJ 1573 Robot Motion

#include <iostream>
#include <queue>
#include <vector>
#include <algorithm>
#include <stack>

using namespace std;

#define debug(x) cout<<#x<<": "<<(x)<<endl;
#pragma warning(disable:4996)

int dx[4] = {-1,0, 1, 0};
int dy[4] = {0, 1, 0,-1};

bool help(int n, int m, int col) {
    //N 0 E 1 S 2 W 3 
    
    vector<vector<int>> a(n,vector<int>(m,-1));
    vector<vector<int>> v(n,vector<int>(m,-1));

    for (size_t i = 0; i < n; ++i) {
        for (size_t j = 0; j < m; ++j) {
            char c;
            cin >> c;
            switch (c)
            {
            case 'N':a[i][j] = 0; break;
            case 'E':a[i][j] = 1; break;
            case 'S':a[i][j] = 2; break;
            case 'W':a[i][j] = 3; break;
            default:
                break;
            }
        }
    }
    int x = 0;
    int y = col - 1;
    int cnt = 0;

    bool out = true;
    while (x >= 0 && x < n && y >= 0 && y < m) {
        int d = a[x][y];
        if (v[x][y] >= 0) {
            cout << v[x][y] << " step(s) before a loop of "<< cnt-v[x][y] << " step(s)" << endl;
            out = false;
            break;
        }
        v[x][y] = cnt;
        x += dx[d], y += dy[d];
        cnt++;
    }
    if (out) {
        cout << cnt << " step(s) to exit" << endl;
    }
    
    return true;
}

int main()
{
    int n, m, col;
    //freopen("../in1.txt","r",stdin);
    while (cin >> n >> m >> col) {
        if (n == 0 && m==0 && col==0) {
            break;
        }
        help(n,m,col);
    }
    
    return 0;
}