poj 1376 Robot 广搜

//poj 1376//sep9#include <iostream>#include <queue> using namespace std;const int maxN=128;int n,m,sx,sy,sdir,ex,ey;int g[maxN][maxN],vis[maxN][maxN][4];int dx[]={-1,0,1,0};int dy[]={0,1,0,-1};struct NODE{int x,y,pos,time;};int getDir(){char s[20];scanf("%s",s);if(!strcmp(s,"north"))return 0;if(!strcmp(s,"east"))return 1;if(!strcmp(s,"south"))return 2;return 3;}bool check(int x,int y){if(x<1||x>=n||y<1||y>=m)return false;if(g[x][y]||g[x+1][y]||g[x][y+1]||g[x+1][y+1])return false;return true;}int bfs(){queue<NODE> q;NODE a;a.x=sx,a.y=sy,a.pos=sdir,a.time=0;q.push(a);vis[sx][sy][sdir]=1;while(!q.empty()){a=q.front(),q.pop();int nx=a.x,ny=a.y;if(nx==ex&&ny==ey)return a.time;for(int i=1;i<=3;++i){nx+=dx[a.pos];ny+=dy[a.pos];if(!check(nx,ny))break;if(!vis[nx][ny][a.pos]){vis[nx][ny][a.pos]=1;NODE nxt;nxt.x=nx,nxt.y=ny,nxt.pos=a.pos,nxt.time=a.time+1;q.push(nxt);}}for(int i=0;i<4;++i){if(abs(a.pos-i)==2)continue;if(vis[a.x][a.y][i]==1)continue;vis[a.x][a.y][i]=1;NODE nxt;nxt.x=a.x,nxt.y=a.y,nxt.pos=i,nxt.time=a.time+1;q.push(nxt);}}return -1;}int main() {while(scanf("%d%d",&n,&m)==2&&(n+m)){for(int i=1;i<=n;++i)for(int j=1;j<=m;++j)scanf("%d",&g[i][j]);memset(vis,0,sizeof(vis));scanf("%d%d%d%d",&sx,&sy,&ex,&ey);sdir=getDir();if(sx==ex&&sy==ey){printf("0\n");continue;}if(!check(ex,ey)){printf("-1\n");continue;}int ans=bfs();if(ans!=-1)printf("%d\n",ans);elseprintf("-1\n");}return 0;}