hustoj 1017 - Exact cover dancing link
1017 - Exact cover
Time Limit: 15s Memory Limit: 128MB
- DESCRIPTION
- There is an N*M matrix with only 0s and 1s, (1 <= N,M <= 1000). An exact cover is a selection of rows such that every column has a 1 in exactly one of the selected rows. Try to find out the selected rows.
- INPUT
- There are multiply test cases. First line: two integers N, M; The following N lines: Every line first comes an integer C(1 <= C <= 100), represents the number of 1s in this row, then comes C integers: the index of the columns whose value is 1 in this row.
- OUTPUT
- First output the number of rows in the selection, then output the index of the selected rows. If there are multiply selections, you should just output any of them. If there are no selection, just output "NO".
- SAMPLE INPUT
-
6 7
3 1 4 7
2 1 4
3 4 5 7
3 3 5 6
4 2 3 6 7
2 2 7 - SAMPLE OUTPUT
-
3 2 4 6
- HINT
- SOURCE
- dupeng
- dancing link裸題,就不細說了。
-
#include<iostream>
#include<cstdio>
#include<cstdlib>
#include<cstring>
#include<ctime>
#include<cmath>
#include<algorithm>
#include<set>
#include<map>
#include<vector>
#include<string>
#include<queue>
using namespace std;
#ifdef WIN32
#define LL "%I64d"
#else
#define LL "%lld"
#endif
#define MAXN 1100
#define MAXV MAXN*2
#define MAXE MAXV*2
#define INF 0x3f3f3f3f
#define INFL 0x3f3f3f3f3f3f3f3fLL
#define MAXD 100000
typedef long long qword;
inline int nextInt()
{
char ch;
int x=;
bool flag=false;
do
ch=(char)getchar(),flag=(ch=='-')?true:flag;
while(ch<''||ch>'');
do x=x*+ch-'';
while (ch=(char)getchar(),ch<='' && ch>='');
return x*(flag?-:);
} int n,m;
struct DLX_t
{
static const int maxd=;
static const int maxn=;
static const int maxm=;
int L[maxd],R[maxd],U[maxd],D[maxd];
int rw[maxd];
int head;
int topd;
int chd[maxm];
int col[maxd];
int tt[maxm];
int n,m;
vector<int> res;
void init(int nn,int mm)
{
n=nn;m=mm;
topd=;
memset(L,,sizeof(L));
memset(R,,sizeof(R));
memset(D,,sizeof(D));
memset(U,,sizeof(U));
memset(tt,,sizeof(tt));
res.clear();
head=++topd;
L[head]=R[head]=head;
for (int i=;i<=m;i++)
{
chd[i]=++topd;
col[chd[i]]=i;
rw[chd[i]]=;
R[chd[i]]=head;
L[chd[i]]=L[head];
R[chd[i]]=head;
L[R[chd[i]]]=chd[i];
R[L[chd[i]]]=chd[i];
U[chd[i]]=D[chd[i]]=chd[i];
}
}
void Add_row(int r,const vector<int> &vec)
{
int i;
int nowh;
int now;
for (i=;i<(int)vec.size();i++)
{
now=++topd;
rw[now]=r;
col[now]=vec[i];
tt[vec[i]]++;
U[now]=U[chd[vec[i]]];
D[now]=chd[vec[i]];
D[U[now]]=now;
U[D[now]]=now;
}
L[U[chd[vec[]]]]=R[U[chd[vec[]]]]=U[chd[vec[]]];
nowh=U[chd[vec[]]];
for (i=;i<(int)vec.size();i++)
{
R[U[chd[vec[i]]]]=nowh;
L[U[chd[vec[i]]]]=L[nowh];
L[R[U[chd[vec[i]]]]]=U[chd[vec[i]]];
R[L[U[chd[vec[i]]]]]=U[chd[vec[i]]];
}
}
void Finish()
{
vector<int> res2=res;
sort(res2.begin(),res2.end());
printf("%d",(int)res2.size());
for (int i=;i<(int)res2.size();i++)
printf(" %d",res2[i]);
printf("\n");
}
void cover(int c)
{
int i,j;
R[L[chd[c]]]=R[chd[c]];
L[R[chd[c]]]=L[chd[c]];
for (i=D[chd[c]];i!=chd[c];i=D[i])
{
for (j=R[i];j!=i;j=R[j])
{
tt[col[j]]--;
U[D[j]]=U[j];
D[U[j]]=D[j];
}
}
}
void resume(int c)
{
int i,j;
R[L[chd[c]]]=chd[c];
L[R[chd[c]]]=chd[c];
for (i=D[chd[c]];i!=chd[c];i=D[i])
{
for (j=R[i];j!=i;j=R[j])
{
tt[col[j]]++;
U[D[j]]=j;
D[U[j]]=j;
}
}
}
bool dfs()
{
int now=head;
if (L[now]==now)
{
Finish();
return true;
}
int bst=INF,bi=-;
int i,j;
for (i=R[head];i!=head;i=R[i])
{
if (tt[col[i]]<bst)
{
bst=tt[i];
bi=i;
}
}
cover(col[bi]);
for (i=D[bi];i!=bi;i=D[i])
{
res.push_back(rw[i]);
for (j=R[i];j!=i;j=R[j])
cover(col[j]);
if (dfs())return true;
res.pop_back();
for (j=R[i];j!=i;j=R[j])
resume(col[j]);
}
resume(col[bi]);
return false;
}
}DLX;
vector<int> vec;
int main()
{
freopen("input.txt","r",stdin);
//freopen("output.txt","w",stdout);
int i,j,k;
int x,y,z;
while (~scanf("%d%d",&n,&m))
{
DLX.init(n,m);
for (i=;i<=n;i++)
{
scanf("%d",&y);
vec.clear();
for (j=;j<=y;j++)
{
scanf("%d",&x);
vec.push_back(x);
}
sort(vec.begin(),vec.end());
DLX.Add_row(i,vec);
}
if (!DLX.dfs())
printf("NO\n");
}
return ;
}
hustoj 1017 - Exact cover dancing link的更多相关文章
- HUST 1017 Exact cover (Dancing links)
1017 - Exact cover 时间限制:15秒 内存限制:128兆 自定评测 6110 次提交 3226 次通过 题目描述 There is an N*M matrix with only 0 ...
- [ACM] HUST 1017 Exact cover (Dancing Links,DLX模板题)
DESCRIPTION There is an N*M matrix with only 0s and 1s, (1 <= N,M <= 1000). An exact cover is ...
- Dancing Link --- 模板题 HUST 1017 - Exact cover
1017 - Exact cover Problem's Link: http://acm.hust.edu.cn/problem/show/1017 Mean: 给定一个由0-1组成的矩阵,是否 ...
- HUST 1017 - Exact cover (Dancing Links 模板题)
1017 - Exact cover 时间限制:15秒 内存限制:128兆 自定评测 5584 次提交 2975 次通过 题目描述 There is an N*M matrix with only 0 ...
- 搜索(DLX):HOJ 1017 - Exact cover
1017 - Exact cover Time Limit: 15s Memory Limit: 128MB Special Judge Submissions: 6751 Solved: 3519 ...
- HUST1017 Exact cover —— Dancing Links 精确覆盖 模板题
题目链接:https://vjudge.net/problem/HUST-1017 1017 - Exact cover 时间限制:15秒 内存限制:128兆 自定评测 7673 次提交 3898 次 ...
- (简单) HUST 1017 Exact cover , DLX+精确覆盖。
Description There is an N*M matrix with only 0s and 1s, (1 <= N,M <= 1000). An exact cover is ...
- [HUST 1017] Exact cover
Exact cover Time Limit: 15s Memory Limit: 128MB Special Judge Submissions: 6012 Solved: 3185 DESCRIP ...
- HUST 1017 Exact cover(DLX精确覆盖)
Description There is an N*M matrix with only 0s and 1s, (1 <= N,M <= 1000). An exact cover is ...
随机推荐
- [Redux] Normalizing the State Shape
We will learn how to normalize the state shape to ensure data consistency that is important in real- ...
- 为centos6.5系统添加epel源
1.进去http://fedoraproject.org/wiki/EPEL 2.因为系统是centos 6.5,所以获取epel-release-latest-6.noarch.rpm的地址(htt ...
- 关于XCode5打开工程闪退的一种解决方案
今天同事遇到一个问题,是关于xcode5打开工程文件一直闪退的问题.后来查看了一下崩溃日志.有如下描述: xception Type: EXC_CRASH (SIGABRT) Exception Co ...
- Ⅰ.AngularJS的点点滴滴--引导
AngularJS已经被很多人像炒冷饭一样炒过啦,大部分都是直接复制官方文档没有说明一些注意事项,不过什么都要从头开始吧 页面引导实例化 1.自动实例化 <html> <script ...
- Orcle数据库恢复
不知道什么原因,服务器上的数据库报错:ORA-01033:ORACLE initialization or shutdown in progress 首先检查:监听文件的主机名及端口号是否更改 数据文 ...
- html input[type=file] css样式美化【转藏】
相信做前端的都知道了,input[type=file]和其他输入标签不一样,它的事件必须是在触发自身元素上,而不能是其他元素.所以不能简单的把input隐藏,放个button上去. <a hre ...
- .net单元测试——常用测试方式(异常模拟、返回值测试、参数测试、数据库访问代码测试)
最近在看.net单元测试艺术,我也喜欢单元测试,今天介绍一下如何测试异常.如何测试返回值.如何测试模拟对象的参数传递.如何测试数据库访问代码.单元测试框架使用的是NUnit,模拟框架使用的是:Rhin ...
- Android常用错误解决汇总
一.No active compatible AVD's or devices found. Relaunch this configuration after connecting a device ...
- javascript - 图片的幻灯片效果
javascript 代码: <script type="text/javascript"> function select_play() { var select_p ...
- mysql 修改root密码多种方法
方法1: 用SET PASSWORD命令 mysql -u root mysql> SET PASSWORD FOR 'root'@'localhost' = PASSWORD('newpa ...