（poj 3322 Bloxorz I）<爆搜？>

传送门

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Solution

居然1A太突然

这道题最重要的是状态的表示
vis[x][y][0]表示位置为（x，y）且是竖着放
vis[x][y][1]表示位置为（x，y）且是横着放，占（x，y）和（x+1，y）两个位置
vis[x][y][2]表示位置为（x，y）且是横着放，占（x，y）和（x，y+1）两个位置
最后注意判断可行就好

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Code

// by spli
#include<cstring>
#include<algorithm>
#include<iostream>
#include<cstdio>
#include<queue>
#define y1 ccccc
using namespace std;

const int N=510;
int n,m;
char s[N][N];
int tx,ty;
bool vis[N][N][4];
struct node{
    int x,y,t,k;//t表示步数,k表示状态
};
queue<node>q;

void bfs(){
    node f;
    int x,y,t;
    while(!q.empty()){
        f=q.front();
        q.pop();
        x=f.x;y=f.y;t=f.t;
        if(x<1||x>n||y<1||y>m) continue;
        if(f.k==0&&s[x][y]=='E') continue;
        if(f.k==1&&x+1>n) continue;
        if(f.k==2&&y+1>m) continue;
        if(x==tx&&y==ty&&f.k==0){
            printf("%d\n",t);
            return;
        }
        if(f.k==0){
            if(!vis[x+1][y][1]&&x+1<=n) q.push((node){x+1,y,t+1,1}),vis[x+1][y][1]=1;
            if(!vis[x-2][y][1]&&x-2>=1) q.push((node){x-2,y,t+1,1}),vis[x-2][y][1]=1;
            if(!vis[x][y+1][2]&&y+1<=m) q.push((node){x,y+1,t+1,2}),vis[x][y+1][2]=1;
            if(!vis[x][y-2][2]&&y-2>=1) q.push((node){x,y-2,t+1,2}),vis[x][y-2][2]=1;
        }
        if(f.k==1){
            if(!vis[x+2][y][0]&&s[x+2][y]!='E'&&x+2<=n) q.push((node){x+2,y,t+1,0}),vis[x+2][y][0]=1;
            if(!vis[x-1][y][0]&&s[x-1][y]!='E'&&x-1>=1) q.push((node){x-1,y,t+1,0}),vis[x-1][y][0]=1;
            if(!vis[x][y+1][1]&&y+1<=m) q.push((node){x,y+1,t+1,1}),vis[x][y+1][1]=1;
            if(!vis[x][y-1][1]&&y-1>=1) q.push((node){x,y-1,t+1,1}),vis[x][y-1][1]=1;
        }
        if(f.k==2){
            if(!vis[x+1][y][2]&&x+1<=n) q.push((node){x+1,y,t+1,2}),vis[x+1][y][2]=1;
            if(!vis[x-1][y][2]&&x-1>=1) q.push((node){x-1,y,t+1,2}),vis[x-1][y][2]=1;
            if(!vis[x][y-1][0]&&s[x][y-1]!='E'&&y-1>=1) q.push((node){x,y-1,t+1,0}),vis[x][y-1][0]=1;
            if(!vis[x][y+2][0]&&s[x][y+2]!='E'&&y+2<=m) q.push((node){x,y+2,t+1,0}),vis[x][y+2][0]=1;
        }
    }
    printf("Impossible\n");return;
}

int main(){
    while(scanf("%d%d",&n,&m)&&n+m){
        memset(vis,0,sizeof(vis));
        while(!q.empty()) q.pop();
        int cnt=0;
        for(int i=1;i<=n;++i){
            scanf("%s",s[i]+1);
            for(int j=1;j<=m;++j){
                if(s[i][j]=='#'){
                    vis[i][j][0]=1;
                    vis[i][j][1]=1;
                    vis[i][j][2]=1;
                    if(i-1>=1) vis[i-1][j][1]=1;
                    if(j-1>=1) vis[i][j-1][2]=1;
                }
                if(s[i][j]=='O') tx=i,ty=j;
                if(s[i][j]=='X') cnt++;
            }
        }
        for(int i=1;i<=n;++i)
            for(int j=1;j<=m;++j){
                if(s[i][j]=='X'){
                    if(cnt==1) q.push((node){i,j,0,0}),vis[i][j][0]=1;
                    if(cnt==2){
                        if(s[i+1][j]=='X') q.push((node){i,j,0,1}),vis[i][j][1]=1;
                        if(s[i][j+1]=='X') q.push((node){i,j,0,2}),vis[i][j][2]=1;
                    }
                    break;
                }
            }
        bfs();
    }
    return 0;
}

你说我代码丑？！
右上角谢谢