POJ 1573

#include <iostream>
#include <stdio.h>
#include <string.h>
using namespace std;
int rows, cols;
const int MAXSIZE = 12;
int start;
char road[MAXSIZE][MAXSIZE];
int visit[MAXSIZE][MAXSIZE];
int path[MAXSIZE][MAXSIZE];
int main(){
//    freopen("../in.txt", "r", stdin);
    while (cin>>rows>>cols>>start&&rows){
        memset(road, -1, sizeof(road));
        memset(visit, 0, sizeof(visit));
        for (int i = 1; i <=rows ; ++i) {
            for (int j = 1; j <=cols ; ++j) {
                char temp;
                cin>>temp;
                road[i][j] = temp;
            }
        }
        //输入结束，开始模拟
        pair<int ,int > point = make_pair(1, start);
        int step1 = 0;
        bool flag = false;
        while (true) {
            if (visit[point.first][point.second]) {
                cout<<path[point.first][point.second]
                    <<" step(s) before a loop of "<<step1-path[point.first][point.second]<<" step(s)"<<endl;
                break;
            }
            int ins = road[point.first][point.second];
            visit[point.first][point.second] = 1;
            path[point.first][point.second] = step1;
            step1++;
            switch (ins) {
                case 'S':
                    point.first++;
                    break;
                case 'N':
                    point.first--;
                    break;
                case 'W':
                    point.second--;
                    break;
                case 'E':
                    point.second++;
                    break;
                default:
                    step1--;
                    flag = true;
                    break;
            }
            if (flag) {
                cout<<step1<<" step(s) to exit"<<endl;
                break;
            }
        }
    }
}