Luogu P2324 [SCOI2005]骑士精神 搜索

刚开始写了个没迭代的。。。结果过了$qwq$

然后迭个代。。更快了。。

#include<cstdio>
#include<iostream>
#define R register int
using namespace std;
inline int g() {
    R ret=,fix=; register char ch; while(!isdigit(ch=getchar())) fix=ch=='-'?-:fix;
    do ret=ret*+(ch^); while(isdigit(ch=getchar())); return ret*fix;
}
const int D[][]=
{{,,,,},
 {,,,,},
 {,,-,,},
 {,,,,,},
 {,,,,}
};
const int dx[]={,,,,-,-,-,-},dy[]={,,-,-,-,-,,};
int T,a[][],ans,xx,yy,mxd;
inline int calc() { R ret=;
    for(R i=;i<=;++i) for(R j=;j<=;++j) ret+=(a[i][j]!=D[i][j]); return ret;
}
inline bool ck(int x,int y) {return x<||x>||y<||y>;}
inline void dfs(int stp,int x,int y,int pre) { R tmp=calc();
    if(stp+tmp>mxd) return ;
    if(tmp==) {ans=min(ans,stp-); return ;}
    for(R i=;i<=;++i) {
        if(pre!=-&&(pre+)%==i) continue;
        R X=x+dx[i],Y=y+dy[i];
        if(ck(X,Y)) continue;
        swap(a[x][y],a[X][Y]); dfs(stp+,X,Y,i);
        swap(a[x][y],a[X][Y]);
    }
}
signed main() {
    T=g(); for(R i=;i<=T;++i) { ans=0x3f3f3f3f;
        for(R i=;i<=;++i) for(R j=;j<=;++j) {
            register char ch; while(ch=getchar(),ch!=''&&ch!=''&&ch!='*');
            a[i][j]=ch-; if(ch=='*') xx=i,yy=j;
        } for(mxd=;mxd<=&&ans==0x3f3f3f3f;++mxd) dfs(,xx,yy,-);  if(ans!=0x3f3f3f3f) printf("%d\n",ans); else printf("-1\n");
    }
} 

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2019.07.03