poj 3083 Children of the Candy Corn（搜索）

http://poj.org/problem?id=3083

题意：迷宫沿着左墙走，和沿着右强的距离以及最短路径的距离分别是多少，当向左走的时候1的位置就是面向左，向右走1的位置面向右，这样可以省去很多事

分析：DFS+BFS

先确定前一位置的方向，再决定下一位置是朝哪个方向旋转

#include<stdio.h>
#include<string.h>
#include<queue>
using namespace std;
const int MAXN=50;
int m,n;
int flag,ans1,ans2,ans3;
char map[MAXN][MAXN];
int cnt[MAXN][MAXN];
int vis[MAXN][MAXN];
struct Node
{
int x,y;
} s,e;

void DFS_L(int x,int y,int step,int face)
{
if(flag) return ;
if(x==e.x && y==e.y)
{
ans1=step;
flag=1;
return ;
}
switch(face)
{
case 1://左
if(map[x+1][y]) DFS_L(x+1,y,step+1,4);
else if(map[x][y-1]) DFS_L(x,y-1,step+1,1);
else if(map[x-1][y]) DFS_L(x-1,y,step+1,2);
else if(map[x][y+1]) DFS_L(x,y+1,step+1,3);
break;
case 2://上
if(map[x][y-1]) DFS_L(x,y-1,step+1,1);
else if(map[x-1][y]) DFS_L(x-1,y,step+1,2);
else if(map[x][y+1]) DFS_L(x,y+1,step+1,3);
else if(map[x+1][y]) DFS_L(x+1,y,step+1,4);
break;
case 3://右
if(map[x-1][y]) DFS_L(x-1,y,step+1,2);
else if(map[x][y+1]) DFS_L(x,y+1,step+1,3);
else if(map[x+1][y]) DFS_L(x+1,y,step+1,4);
else if(map[x][y-1]) DFS_L(x,y-1,step+1,1);

case 4://下
if(map[x][y+1]) DFS_L(x,y+1,step+1,3);
else if(map[x+1][y]) DFS_L(x+1,y,step+1,4);
else if(map[x][y-1]) DFS_L(x,y-1,step+1,1);
else if(map[x-1][y]) DFS_L(x-1,y,step+1,2);
break;
}
}

void DFS_R(int x,int y,int step,int face)
{
if(flag) return ;
if(x==e.x && y==e.y)
{
ans2=step;
flag=1;
return ;
}
switch(face)
{
case 1://右
if(map[x+1][y]) DFS_R(x+1,y,step+1,4);
else if(map[x][y+1]) DFS_R(x,y+1,step+1,1);
else if(map[x-1][y]) DFS_R(x-1,y,step+1,2);
else if(map[x][y-1]) DFS_R(x,y-1,step+1,3);
break;
case 2://上
if(map[x][y+1]) DFS_R(x,y+1,step+1,1);
else if(map[x-1][y]) DFS_R(x-1,y,step+1,2);
else if(map[x][y-1]) DFS_R(x,y-1,step+1,3);
else if(map[x+1][y]) DFS_R(x+1,y,step+1,4);
break;
case 3://左
if(map[x-1][y]) DFS_R(x-1,y,step+1,2);
else if(map[x][y-1]) DFS_R(x,y-1,step+1,3);
else if(map[x+1][y]) DFS_R(x+1,y,step+1,4);
else if(map[x][y+1]) DFS_R(x,y+1,step+1,1);

case 4://下
if(map[x][y-1]) DFS_R(x,y-1,step+1,3);
else if(map[x+1][y]) DFS_R(x+1,y,step+1,4);
else if(map[x][y+1]) DFS_R(x,y+1,step+1,1);
else if(map[x-1][y]) DFS_R(x-1,y,step+1,2);
break;
}
}

int BFS()
{
int i;
queue<Node> Q;
Q.push(s);
Node head,next;
while(!Q.empty())
{
head=Q.front();
Q.pop();

if(!vis[head.x-1][head.y] && map[head.x-1][head.y])
{
next.x=head.x-1;
next.y=head.y;
Q.push(next);
vis[next.x][next.y]=1;
cnt[next.x][next.y]=cnt[head.x][head.y]+1;
}
if(!vis[head.x+1][head.y]&& map[head.x+1][head.y])
{
next.x=head.x+1;
next.y=head.y;
Q.push(next);
vis[next.x][next.y]=1;
cnt[next.x][next.y]=cnt[head.x][head.y]+1;
}
if(!vis[head.x][head.y-1]&& map[head.x][head.y-1])
{
next.x=head.x;
next.y=head.y-1;
Q.push(next);
vis[next.x][next.y]=1;
cnt[next.x][next.y]=cnt[head.x][head.y]+1;
}
if(!vis[head.x][head.y+1] && map[head.x][head.y+1])
{
next.x=head.x;
next.y=head.y+1;
Q.push(next);
vis[next.x][next.y]=1;
cnt[next.x][next.y]=cnt[head.x][head.y]+1;
}
vis[head.x][head.y]=1;
if(e.x==head.x && e.y==head.y) return cnt[head.x][head.y];
}
return cnt[head.x][head.y];
}

int main()
{
int T,i,j;
scanf("%d",&T);
while(T--)
{
memset(map,0,sizeof(map));
scanf("%d%d",&m,&n);
for(i=1; i<=n; i++)
{
scanf("%s",map[i]+1);
for(j=1; map[i][j]; j++)
{
if(map[i][j]=='.') map[i][j]=1;
else if(map[i][j]=='#') map[i][j]=0;
if(map[i][j]=='S')
{
s.x=i;
s.y=j;
map[i][j]=1;
}
else if(map[i][j]=='E')
{
e.x=i;
e.y=j;
map[i][j]==1;
}
}
}
flag=0;
DFS_L(s.x,s.y,1,1);
flag=0;
DFS_R(s.x,s.y,1,1);
memset(cnt,0,sizeof(cnt));
memset(vis,0,sizeof(vis));
ans3=BFS();
printf("%d %d %d\n",ans1,ans2,ans3+1);
}
return 0;
}