poj3009

#include <iostream>
#include <stdio.h>
using namespace std;
#define INF 100000000

int W,H;
int M[32][32];
int minstep = INF;
int sx,sy,ex,ey;
int dx[4] = {-1,1,0,0};
int dy[4] = {0,0,-1,1};
void dfs(int step,int posx,int posy){
if(step==10){
return;
}
for(int i=0;i<4;i++){
int newx = posx + dx[i];
int newy = posy + dy[i];
if(newx>=0 && newx<H && newy>=0 && newy<W && M[newx][newy]!=1){
while(newx>=0 && newx<H && newy>=0 && newy<W && M[newx][newy]==0){
newx = newx + dx[i];
newy = newy + dy[i];
}
if(newx<0 || newx>=H || newy<0 || newy>=W){
if( (newx-dx[i] == ex) && (newy-dy[i] == ey) && (step+1)<minstep )minstep = step+1;
continue;
}
else if(newx==ex && newy == ey){
if((step+1)<minstep) minstep = step+1;
return;
}else{
M[newx][newy] = 0;
newx -= dx[i];
newy -= dy[i];
dfs(step+1,newx,newy);
M[newx+dx[i]][newy+dy[i]] = 1;
}
}else{
continue;
}
}
}
int main(int argc, const char * argv[]) {
cin>>W>>H;
int i,j;

while(W!=0 || H!=0){
for(i=0;i<H;i++){
for(j=0;j<W;j++){
cin>>M[i][j];
if(M[i][j]==2) { M[i][j] = 0; sx = i ; sy = j ; }
if(M[i][j]==3) { ex = i ; ey = j ; }
}
}
dfs(0,sx,sy);
if(minstep == INF)minstep = -1;
cout<<minstep<<endl;
cin>>W>>H;
minstep = INF;
}
return 0;
}