【BZOJ】1085: [SCOI2005]骑士精神

题目链接：http://www.lydsy.com/JudgeOnline/problem.php?id=1085

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$${if (cs+val-1>ans) return ;}$$

#include<iostream>
#include<cstdio>
#include<algorithm>
#include<vector>
#include<cstdlib>
#include<cmath>
#include<cstring>
using namespace std;
#define maxn 10010
#define llg long long 
#define yyj(a) freopen(a".in","r",stdin),freopen(a".out","w",stdout);
llg n,m,ans,stx,sty,T;
bool pd;
char s[10][10];
char aim[8][8]={"000000","011111","001111","000*11","000001","000000"}; 
llg p[8][2]={{1,2},{-1,2},{-1,-2},{1,-2},{-2,-1},{-2,1},{2,-1},{2,1}};  

llg cal()
{
    llg sum=0;
    for (llg i=1;i<=5;i++) 
        for (llg j=1;j<=5;j++)
            if (s[i][j]!=aim[i][j]) sum++;
    return sum;
}

void ss(llg cs,llg x,llg y)
{
    if (cs>ans || pd) return ;
    llg val=cal();
    if (val==0) {pd=1; return ;}
    if (cs>ans) return ;
    if (cs+val-1>ans) return ;
    for (llg i=0;i<8;i++)
    {
        llg nx=x+p[i][0],ny=y+p[i][1];
        if (nx<1 || ny<1 || nx>5 || ny>5) continue;
        swap(s[x][y],s[nx][ny]);
        ss(cs+1,nx,ny);
        swap(s[x][y],s[nx][ny]);
    }
}

int main()
{
    yyj("bzoj1085");
    cin>>T;
    while (T--)
    {
        for (llg i=1;i<=5;i++) cin>>(s[i]+1);
        for (llg i=1;i<=5;i++)
            for (llg j=1;j<=5;j++)
                if (s[i][j]=='*')
                    stx=i,sty=j;
        for (ans=0;ans<=15;ans++)
        {
            pd=0;
            ss(0,stx,sty);
            if (pd) break;
        }
        if (ans==16) ans=-1;
        cout<<ans<<endl;
    }
    return 0;
}