The Pilots Brothers' refrigerator

Posted 2022-09-14 baseai

题目地址

题解

我是蒟蒻，所以我只会打一个暴力。

这道题就是状压+暴力Bfs，（~~连双向Bfs优化都不用，跟别说A*什么的了~~）

Code

#include<bits/stdc++.h>
#define MAXBIT 150007
using namespace std;
bool vis[MAXBIT];
struct Node 
    int state,step;
;
struct Pre 
    int state,x,y;
pre[MAXBIT];
void print_ans(int state) 
    if(pre[state].state==-1) 
        return ;
    
    print_ans(pre[state].state);
    printf("%d %d\n",pre[state].x,pre[state].y);

void Bfs(int s,int t)  //?′μ?￡???μ? 
    if(s==0) 
        puts("0");
        return ;
    
    queue<Node> q; int val[5][5],tmp[5][5]; //tp=tempê?áùê±êy×é 
    vis[s] = 1; q.push((Node)s,0);
    while(!q.empty()) 
        int now = q.front().state ,step = q.front().step; q.pop();
        memset(val,0,sizeof(val));
        int tmpnow = now;
        for(int i=4;i>=1;--i)
            for(int j=4;j>=1;--j) 
                val[i][j] = tmpnow & 1; tmpnow >>= 1;
            
        //test
            
        for(int x=1;x<=4;++x) for(int y=1;y<=4;++y) 
            memset(tmp,0,sizeof(tmp));
            for(int i=1;i<=4;++i)
                for(int j=1;j<=4;++j)
                    tmp[i][j] = val[i][j];
            for(int i=1;i<=4;++i) 
                tmp[x][i] ^= 1; tmp[i][y] ^= 1;
            
            tmp[x][y] ^= 1;
            int nst = 0;    //new state
            for(int i=1;i<=4;++i) for(int j=1;j<=4;++j) 
                nst = (nst<<1) + tmp[i][j];
            
            if(!vis[nst]) 
                vis[nst] = 1; pre[nst].state = now; pre[nst].x = x; pre[nst].y = y;
                q.push((Node)nst,step+1);
            
            if(nst == 0) 
                printf("%d\n",step+1);
                print_ans(nst);
                return ;
            
        
    

int main()

    char ch; int s=0;
    for(int i=1;i<=4;++i)
        for(int j=1;j<=4;++j) 
            scanf(" %c",&ch); s = (s<<1) + (ch=='+' ? 1 : 0);   //??±ê?íê?è??aá?
        
    pre[s].state = -1;
    Bfs(s,0);
    return 0;