DLX 模板

来源：互联网发布：linux终端快捷键设置编辑：程序博客网时间：2024/06/05 06:03
//以hust1017为例
#include<stdio.h>#include<string.h>#define N 1100#define M 1100#define V N*M#define INF 100000000int D[V+1],U[V+1],L[V+1],R[V+1],C[V+1],mark[V+1];int S[M+1],H[N+1];void remove(int c){int i,j;R[L[c]]=R[c];L[R[c]]=L[c];for(i=D[c];i!=c;i=D[i])for(j=R[i];j!=i;j=R[j]) { U[D[j]]=U[j]; D[U[j]]=D[j]; --S[C[j]]; }}void resume(int c){int i,j;for(i=U[c];i!=c;i=U[i])for(j=L[i];j!=i;j=L[j]) { U[D[j]]=j; D[U[j]]=j; ++S[C[j]]; }R[L[c]]=c;L[R[c]]=c;}int size;void Link(int r,int c) {    S[c]++; C[size]=c;//插入一列的头部    U[size]=U[c]; D[U[c]]=size;      D[size]=c; U[c]=size;//插入一行的头部    if(H[r]==-1) H[r]=L[size]=R[size]=size;    else {        L[size]=L[H[r]];R[L[H[r]]]=size;        R[size]=H[r];L[H[r]]=size;    }    mark[size]=r;    ++size;}int O[N+1],head,n,m;int dfs(int k){int i,j,c,Max=INF;if(R[head]==head){printf("%d",k);        for(i=0;i<k;i++)            printf(" %d",mark[O[i]]);        printf("\n");return 1;}for(i=R[head];i!=head;i=R[i])if(S[i]<Max){ c=i; Max=S[i]; }remove(c); for(i=D[c];i!=c;i=D[i]){O[k]=i;for(j=R[i];j!=i;j=R[j]) remove(C[j]);if(dfs(k+1)) return 1;for(j=L[i];j!=i;j=L[j]) resume(C[j]);}resume(c);return 0;}void init(int m){int i;for(i=0;i<=m;i++) {S[i]=0;D[i]=U[i]=i;L[i+1]=i;R[i]=i+1;}R[m]=head=0;L[0]=m;size=m+1;memset(H,-1,sizeof(H));memset(mark,0,sizeof(mark));}int main() {    int i,j,num;    while(scanf("%d%d",&n,&m)!=EOF) {init(m);        for(i=1;i<=n;i++) {            scanf("%d",&num);            while(num --) {                scanf("%d",&j);                Link(i , j);            }        }        if(!dfs(0)) puts("NO");    }    return 0;}