hust1017Exact cover(Dancing Links)

题目链接:点这里!!!


题解:Dancing Links第一题,抄了几下kuangbin的板子,感觉这东西真TM的吊!!

推荐篇blog:http://www.cnblogs.com/grenet/p/3145800.html



代码:

#include
#include
#include
#include
#include
#include
#include
#include
#include
#include
#include
#include
#include
#define pb push_back
#define pa pair
#define clr(a,b) memset(a,b,sizeof(a))
#define lson lr<<1,l,mid
#define rson lr<<1|1,mid+1,r
#define bug(x) printf("%d++++++++++++++++++++%d\n",x,x)
#define key_value ch[ch[root][1]][0]
#pragma comment(linker, "/STACK:102400000000,102400000000")
typedef  long long LL;
const LL  MOD = 1000000007;
const int N = 55;
const int maxn = 1e6+15;
const int letter = 130;
const int INF = 1e9;
const double pi=acos(-1.0);
const double eps=1e-10;
using namespace std;
inline int read()
{
    int x=0,f=1;char ch=getchar();
    while(ch<'0'||ch>'9'){if(ch=='-')f=-1;ch=getchar();}
    while(ch>='0'&&ch<='9'){x=x*10+ch-'0';ch=getchar();}
    return x*f;
}
int n,m;
const int maxnode = 1e5+15;
const int maxh=1000+15;
struct dlx{
    int n,m,size;
    int U[maxnode],D[maxnode],L[maxnode],R[maxnode];
    int row[maxnode],col[maxnode];
    int H[maxh],S[maxh];
    int ansd,ans[maxh];
    void init(int _n,int _m){
        n=_n,m=_m;
        for(int i=0;i<=m;i++){
            S[i]=0;
            U[i]=D[i]=i;
            L[i]=i-1;
            R[i]=i+1;
        }
        R[m]=0,L[0]=m;
        size=m;
        for(int i=1;i<=n;i++) H[i]=-1;
    }
    void link(int r,int c){
        ++S[col[++size]=c];
        row[size]=r;
        D[size]=D[c];
        U[D[c]]=size;
        U[size]=c;
        D[c]=size;
        if(H[r]<0) H[r]=L[size]=R[size]=size;
        else {
            R[size]=R[H[r]];
            L[R[H[r]]]=size;
            L[size]=H[r];
            R[H[r]]=size;
        }
    }
    void remove(int c){
        L[R[c]]=L[c],R[L[c]]=R[c];
        for(int i=D[c];i!=c;i=D[i])
        for(int j=R[i];j!=i;j=R[j]){
            U[D[j]]=U[j];
            D[U[j]]=D[j];
            --S[col[j]];
        }
    }
    void resume(int c){
        for(int i=U[c];i!=c;i=U[i])
            for(int j=L[i];j!=i;j=L[j])
                ++S[col[U[D[j]]=D[U[j]]=j]];
        L[R[c]]=R[L[c]]=c;
    }
    bool dance(int d){
        if(R[0]==0){ansd=d;return true;}
        int c=R[0];
        for(int i=R[0];i!=0;i=R[i])
            if(S[i]


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