51 nod 1211 数独 DLX

原题链接：http://www.51nod.com/onlineJudge/questionCode.html#!problemId=1211

调了挺久的，自己的一份舞蹈链模板……

算是在网上见到的模板中比较短的一份吧(2.2K)

#include<cstdio>
#include<algorithm>
#include<ctime>
#define MN 300000
using namespace std;
int read_p,read_ca;
inline int read(){
    read_p=0;read_ca=getchar();
    while(read_ca<'0'||read_ca>'9') read_ca=getchar();
    while(read_ca>='0'&&read_ca<='9') read_p=read_p*10+read_ca-48,read_ca=getchar();
    return read_p;
}
int n,m,l[MN],r[MN],d[MN],u[MN],X[MN],Y[MN],Z[MN],mmh[MN],st[MN],_MMH,_mmh[MN],_h[MN],map[10][10],_a[MN],top=0,c,Num,_L[MN],s[MN],MMH=0,NN=0,a,num=324,h=0;
bool Bo[MN];
inline void rec(){int x=st[top--];d[u[x]]=x;u[d[x]]=x;l[r[x]]=x;r[l[x]]=x;s[_L[x]]++;}
inline void del(int x){if (Bo[_L[x]]) return;s[_L[x]]--;st[++top]=x;d[u[x]]=d[x];u[d[x]]=u[x];l[r[x]]=l[x];r[l[x]]=r[x];}
inline void tadd(int l,int x){u[d[u[l]]=x]=u[l];d[u[l]=x]=l;_L[x]=l;s[l]++;}
inline void hadd(int x,int y,int z){
    h++;X[h]=x;Y[h]=y;Z[h]=z;
    tadd(x*9-9+y,++num);tadd(x*9-9+z+81,++num);tadd(y*9-9+z+162,++num);tadd(((x-1)/3*3+(y+2)/3)*9-9+z+243,++num);
    r[num-3]=num-2;r[num-2]=num-1;r[num-1]=num;r[num]=num-3;
    l[num-3]=num;l[num-2]=num-3;l[num-1]=num-2;l[num]=num-1;
    _h[num-3]=_h[num-2]=_h[num-1]=_h[num]=h;
}
void work(int p){
    NN++;
    register int i,j,k,o;
    if (MMH==2) return;
    if (!r[0]){
        _MMH=p-1;
        for (i=1;i<=_MMH;i++) _mmh[i]=mmh[i];
        MMH++;
        return;
    }
    int bo=top,t,mr=1e9;c=0;
    for (i=r[0];i;i=r[i]){
        if (d[i]==i) return;
        if (mr>s[i]){
            mr=s[i];
            t=i;
        }
    }
    for (i=d[t];i!=t;i=d[i]){
        mmh[p]=_h[i];
        for (j=i;;j=r[j]){
            for (k=j;;k=d[k]){
                for (o=k;;o=r[o]){
                    if (Bo[o]) break;
                    Bo[_a[++c]=o]=1;
                    if (r[o]==k||o<=324) break;
                }
                if (d[k]==j) break;
            }
            if (r[j]==i) break;
        }
        for (j=c;j;j--) del(_a[j]);
        while (c) Bo[_a[c--]]=0;
        work(p+1);
        while (top>bo) rec();
    }
}
int main(){
    register int i,j,k;
    for (i=0;i<=num;i++) l[i]=i==0?num:i-1,r[i]=i==num?0:i+1,u[i]=d[i]=i;
    for (i=1;i<=9;i++)
    for (j=1;j<=9;j++){
        a=read();
        if (a) hadd(i,j,a);else
        for (k=1;k<=9;k++) hadd(i,j,k);
    }
    work(1);
    if (MMH!=1) return printf("No Solution
"),0;
    for (i=1;i<=_MMH;i++) map[X[_mmh[i]]][Y[_mmh[i]]]=Z[_mmh[i]];
    for (i=1;i<=9;printf("
"),i++)
    for (j=1;j<=9;j++) printf("%d ",map[i][j]);
}