UVA 10116 - Robot Motion

#include <iostream>#include <memory.h>#include <cstdio>using namespace std;#define MAX 15char table[128];char grid[MAX][MAX];bool vis[MAX][MAX];int x[200],y[200];int di[]={-1,1,0,0},dj[]={0,0,-1,1};int n,m,s;int main(){table['N']=0,table['S']=1,table['W']=2,table['E']=3;while(scanf("%d %d %d",&n,&m,&s)==3){if(!n&&!m&&!s)break;for (int i=0;i<n;++i)scanf("%s",grid[i]);memset(vis,0,sizeof(vis));int cnt=0,curi=0,curj=s-1,inLoop=0,loopNum=0;vis[curi][curj]=1;while (1){int ti=curi,tj=curj;curi=curi+di[table[grid[ti][tj]]],curj=curj+dj[table[grid[ti][tj]]];if(curi>=0&&curi<n&&curj>=0&&curj<m){if(vis[curi][curj]){int i;for (i=cnt-1;i>=0;--i){if(x[i]==curi&&y[i]==curj)break;}inLoop=1;loopNum=cnt-i;break;}else{vis[curi][curj]=1;x[cnt]=curi,y[cnt]=curj;cnt++;}}else break;}if(inLoop){printf("%d step(s) before a loop of %d step(s)\n",cnt-loopNum+1,loopNum);}else{printf("%d step(s) to exit\n",cnt+1);}}return 0;}