POJ 2977 Box walking 长方体表面两点距离

POJ2977 小学生的考试题，暴力得出O(1)的解法

#include<iostream>
#include<cstdio>
#include<cstdlib>
#include<cstring>
#include<cmath>
#include<vector>
using namespace std;

int ans;
void turn(int i,int j,int x,int y,int z,int x0,int y0,int L,int W,int H)
{
 if(z==0)ans=min(ans,(x-x0)*(x-x0)+(y-y0)*(y-y0));
 	else
 		{
 		 if(i>=0&&i<2)
		  turn(i+1,j,H-z,y,x,x0+H,y0,H,W,L);
 		 if(j>=0&&j<2)
		  turn(i,j+1,x,H-z,y,x0,y0+H,L,H,W);
 		 if(i<=0&&i>-2)
		  turn(i-1,j,z,y,L-x,x0-L,y0,H,W,L);
 		 if(j<=0&&j>-2)
		  turn(i,j-1,x,z,W-y,x0,y0-W,L,H,W);
		}
}

int rect_dist(int L,int W,int H,int x1,int y1,int z1,int x2,int y2,int z2)
{
 if(z1!=0&&z1!=H)
 	if(y1==0||y1==W)
 		swap(y1,z1),swap(y2,z2),swap(W,H);
 		else 
 			swap(x1,z1),swap(x2,z2),swap(L,H);
 if(z1==H)
 	z1=0,z2=H-z2;
ans=1<<30;
turn(0,0,x2,y2,z2,x1,y1,L,W,H);
return ans;
}

int main()
{//freopen("t.txt","r",stdin);
 int L,W,H,x,y,z;
 while(scanf("%d%d%d%d%d%d",&L,&W,&H,&x,&y,&z))
 	{
 	 if(L==0&&W==0&&H==0&&x==0&&y==0&&z==0)return 0;
 	 printf("%d
",rect_dist(L,W,H,0,0,0,x,y,z));
	}
 return 0;
}