hacker cup 2015 资格赛

// File Name: c.cpp
// Author: darkdream
// Created Time: 2015年01月10日 星期六 20时10分04秒

#include<vector>
#include<list>
#include<map>
#include<set>
#include<deque>
#include<stack>
#include<bitset>
#include<algorithm>
#include<functional>
#include<numeric>
#include<utility>
#include<sstream>
#include<iostream>
#include<iomanip>
#include<cstdio>
#include<cmath>
#include<cstdlib>
#include<cstring>
#include<ctime>
#define LL long long

using namespace std;
int mp[5][105][105];
int bex , bey ;
int enx,  eny ;
int n , m;
int vis[105][105][105];
void fillmap(int k )
{
for(int i = 1;i <= n;i ++)
{
for(int j = 1;j <= m ;j ++)
{
if(mp[k][i][j]  == 2)
{
int x = i + 1;
while(mp[k][x][j] == 1 || mp[k][x][j] == -1)
{
mp[k][x][j] = -1;
x ++ ;
}
} else if(mp[k][i][j] == 3)
{
int x = i - 1;
while(mp[k][x][j] == 1 || mp[k][x][j] == -1)
{
mp[k][x][j] = -1;
x -- ;
}
} else if(mp[k][i][j] == 4)
{
int x = j + 1;
while(mp[k][i][x] == 1 || mp[k][i][x] == -1)
{
mp[k][i][x] = -1;
x ++;
}
}else if(mp[k][i][j] == 5)
{
int x = j -1;
while(mp[k][i][x] == 1 || mp[k][i][x] == -1)
{
mp[k][i][x] = -1;
x --;
}
}
}
}
}
void print(int k )
{
for(int i = 1;i <= n;i ++)
{
for(int j = 1;j <= m ;j ++)
{
printf("%d ",mp[k][i][j]);
}
printf("\n");
}
printf("\n");
}
void changeto(int k )
{
for(int i = 1;i <= n;i ++)
{
for(int j = 1;j <= m;j ++)
{
if(mp[k-1][i][j] == 0)
mp[k][i][j] == 0;
else if(mp[k-1][i][j] == 1)
mp[k][i][j] = 1;
else if(mp[k-1][i][j] == 2)
mp[k][i][j] = 5;
else if(mp[k-1][i][j] == 3)
mp[k][i][j] = 4;
else if(mp[k-1][i][j] == 4)
mp[k][i][j] = 2;
else if(mp[k-1][i][j] == 5)
mp[k][i][j] = 3;
else if(mp[k-1][i][j] == -1)
mp[k][i][j] = 1;
}
}
fillmap(k);
//print(k);
}
struct node{
int x,y,step,flag;
node(){

}
node(int _x ,int _y ,int _step ,int _flag)
{
x = _x;
y = _y;
step = _step;
flag = _flag;
}
}qu[101000];
int xadd[] = {1,-1,0,0};
int yadd[] = {0,0,-1,1};
int bfs()
{
memset(vis,0,sizeof(vis));
qu[1] = node(bex,bey,0,0);
vis[0][bex][bey] = 1;
int l = 1;
int r = 1;
while(l <= r)
{
// printf("%d %d\n",qu[l].x,qu[l].y);
if(qu[l].x == enx && qu[l].y == eny)
{
return  qu[l].step;
}
int k = (qu[l].flag + 1)%4;
for(int i = 0;i <= 3; i ++)
{
int tx = qu[l].x + xadd[i];
int ty = qu[l].y + yadd[i];
if(mp[k][tx][ty] == 1 &&  vis[k][tx][ty] != 1)
{
vis[k][tx][ty] = 1;
r ++ ;
qu[r] = node(tx,ty,qu[l].step + 1, k);
}
}
l ++ ;
}
return 0 ;
}
int main(){
freopen("in.txt","r",stdin);
freopen("out","w",stdout);
int T;
scanf("%d",&T);
for(int ca = 1; ca <= T; ca ++)
{
scanf("%d %d",&n,&m);
char str[1000];
memset(mp,0,sizeof(mp));
for(int i = 1;i <= n;i ++)
{
scanf("%s",&str[1]);
for(int j = 1;j <= m;j ++)
{
if(str[j] == 'S')
{
bex = i ;
bey = j ;
mp[0][i][j] = 1;
}else if(str[j] == 'G')
{
mp[0][i][j] = 1;
enx = i ;
eny = j;
}else if(str[j] == '#')
{
mp[0][i][j] = 0 ;
}else if(str[j] ==  '.')
mp[0][i][j] = 1 ;
else if(str[j] == 'v')
mp[0][i][j] = 2;
else if(str[j] == '^')
mp[0][i][j] =3;
else if(str[j] == '>')
mp[0][i][j] =4 ;
else if(str[j] == '<')
mp[0][i][j] =5;
}
}

fillmap(0);
changeto(1);
changeto(2);
changeto(3);
//for(int i = 0 ;i <= 3;i ++ )
//  print(i);
int ok = bfs();
printf("Case #%d: ",ca);
if(ok == 0 )
printf("impossible\n");
else printf("%d\n",ok);
}
return 0;
}