【BZOJ】1085: [SCOI2005]骑士精神

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

---

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

 #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[][];
 char aim[][]={"","","","000*11","",""};
 llg p[][]={{,},{-,},{-,-},{,-},{-,-},{-,},{,-},{,}};  

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

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