P3930 SAC E#1 - 一道大水题 Knight

 

TLE，额 ，有空再写吧。

#include<queue>
#include<cstdio>
#include<vector>
#include<algorithm>
#include<cmath>
using namespace std;
const int dx[8]={1,1,-1,-1,2,2,-2,-2},dy[8]={2,-2,2,-2,1,-1,1,-1};
const int N = 80;
struct node{
    int x,y;
    int step,state;
};
queue<node>q;
int n,sx,sy;
char a[N][N];
int id[N][N],tot;
bool Vis[N][N][20000];
bool check( int  state,int x ,int  y)
{
    if(Vis[x][y][state])        
        return 0;
    //下 
    for(int i=x+1;i<=n;i++)
    if(a[i][y]!='.'&& !(state&(1<<id[x][y])))
    {
        if(a[i][y]=='C'||a[i][y]=='Q')
        return 0;
        break;
    }
    //上 
    for(int i=x-1;i<=1;i--)
    if(a[i][y]!='.'&& !(state&(1<<id[i][y])))
    {
        if(a[i][y]=='C'||a[i][y]=='Q')
        return 0;
        break;
    }
    //左
    for(int j=y+1;j<=n;j++)
    if(a[x][j]!='.'&&!(state&(1<<id[x][j])))
    {
        if(a[x][j]=='C'||a[x][j]=='Q')
            return 0;
        break;
    }
    //右
    for(int j=y-1;j>=1;j--)
    if(a[x][j]!='.'&&!(state&(1<<id[x][j])))
    {
        if(a[x][j]=='C'||a[x][j]=='Q')
            return 0;
        break;
    }
    //左上
    for(int i=x-1,j=y-1;i>=1&&j>=1;i--,j--)
    if(a[i][j]!='.'&&!(state&(1<<id[i][j])))
    {
        if(a[i][j]=='B'||a[i][j]=='Q')
            return 0;
        break;
    }
    //右上
    for(int i=x+1,j=y-1;i<=n&&j>=1;i++,j--)
    if(a[i][j]!='.'&&!(state&(1<<id[i][j])))
    {
        if(a[i][j]=='B'||a[i][j]=='Q')
            return 0;
        break;
    }
    //左下
    for(int i=x-1,j=y+1;i>=1&&j<=n;i--,j++)
    if(a[i][j]!='.'&&!(state&(1<<id[i][j])))
    {
        if(a[i][j]=='B'||a[i][j]=='Q')
            return 0;
        break;
    }
    //右下
    for(int i=x+1,j=y+1;i<=n&&j<=n;i++,j++)
    if(a[i][j]!='.'&&!(state&(1<<id[i][j])))
    {
        if(a[i][j]=='B'||a[i][j]=='Q')
            return 0;
        break;
    }
    int X,Y;
    for(int i=0;i<=7;i++)
    {
        X=x+dx[i];Y=y+dy[i];
        if(X>=1&&X<=n&&Y>=1&&Y<=n&&a[X][Y]=='K')
        return 0;
    }
    if(x!=1&&((y!=n&&a[x-1][y+1]=='P'&&!(state&(1<<(id[x-1][y+1]))||(y!=1&&a[x-1][y-1]=='P'&&!(state&(1<<id[x-1][y-1])))))))
        return 0;
    for(int i=x-1;i<=x+1;i++)
    for(int j=y-1;j<=y+1;j++)
    if(x>=1&&x<=n&&y>=1&&y<=n)
    {
        if(a[i][j]=='X')    return 0;
    } 
    return 1;
}
void work()
{
    queue<node>q;tot=0;    
    for(int i=1;i<=n;i++)
    for(int j=1;j<=n;j++)
    {
        id[i][j]=-1,a[i][j]=0;
        for(int k=0;k<=(1<<15);k++)
        Vis[i][j][k]=0;
    }
    
    for(int i=1;i<=n;i++)
    {
        scanf("%s",a[i]+1);
        for(int j=1;j<=n;j++)
        {
            if(a[i][j]=='O')
                sx=i,sy=j,a[i][j]='.';
            else 
            if(a[i][j]=='C'||a[i][j]=='K'||a[i][j]=='Q'||a[i][j]=='X'||a[i][j]=='P')
                id[i][j]=tot++;
            else a[i][j]='.';        
        }            
    }
    if(!check(0,sx,sy))
    {
        cout<<-1;
        return;
    }    
    q.push((node){sx,sy,0,0});
    node now;int x,y,state;
    while(!q.empty())
    {
        now=q.front();q.pop();
        state=now.state;
        for(int i=0;i<8;i++)
        {
            x=now.x+dx[i];y=now.y+dy[i];
            if(x<1||x>n||y<1||y>n)    continue;
            if(a[x][y]=='X')
            {
                printf("%d\n",now.step+1);
                return;
            }
            if(a[x][y]!='.')
                state|= 1<<id[x][y];
            if(check(state,x,y))
                Vis[x][y][state]=1,q.push((node){x,y,now.step+1,state}); 
        }
    }
    cout<<-1;
}
int main()
{
     while(scanf("%d",&n))
        work();
    return 0;
}