UVA 11825(Hacker's Crackdown-集合)

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给一个集合U和一堆子集
最多把子集分成多少份,使每份的并为全集U?

集合子集的遍历 for(int S0 = S; S0; S0 = (S0-1)&S)

#include<bits/stdc++.h>using namespace std;#define For(i,n) for(int i=1;i<=n;i++)#define Fork(i,k,n) for(int i=k;i<=n;i++)#define Rep(i,n) for(int i=0;i<n;i++)#define ForD(i,n) for(int i=n;i;i--)#define ForkD(i,k,n) for(int i=n;i>=k;i--)#define RepD(i,n) for(int i=n;i>=0;i--)#define Forp(x) for(int p=Pre[x];p;p=Next[p])#define Forpiter(x) for(int &p=iter[x];p;p=Next[p])  #define Lson (o<<1)#define Rson ((o<<1)+1)#define MEM(a) memset(a,0,sizeof(a));#define MEMI(a) memset(a,127,sizeof(a));#define MEMi(a) memset(a,128,sizeof(a));#define INF (2139062143)#define F (100000007)#define pb push_back#define mp make_pair #define fi first#define se second#define vi vector<int> #define pi pair<int,int>#define SI(a) ((a).size())typedef long long ll;typedef unsigned long long ull;ll mul(ll a,ll b){return (a*b)%F;}ll add(ll a,ll b){return (a+b)%F;}ll sub(ll a,ll b){return (a-b+llabs(a-b)/F*F+F)%F;}void upd(ll &a,ll b){a=(a%F+b%F)%F;}int read(){    int x=0,f=1; char ch=getchar();    while(!isdigit(ch)) {if (ch=='-') f=-1; ch=getchar();}    while(isdigit(ch)) { x=x*10+ch-'0'; ch=getchar();}    return x*f;} #define MAXN (17)int f[1<<17],P[1<<17],cover[1<<17];int main(){//  freopen("uva11825.in","r",stdin);//  freopen(".out","w",stdout);    int n,kcase=1;    while (n=read()) {        int ALL=(1<<n)-1;        Rep(i,n) {            P[i]=1<<i;            int m=read();            while (m--) P[i]|=1<<( read() );        }           Rep(S,1<<n) {            cover[S] = 0;            Rep(i,n) if (S & (1<<i) ) cover[S]|=P[i];        }         Rep(S,1<<n) {            f[S]=0;            for(int S0 = S; S0; S0 = (S0-1)&S)                if (cover[S0]==ALL)                     f[S] = max( f[S], f[S-S0] + 1);        }        printf("Case %d: %d\n",kcase++,f[ALL]);    }    return 0;}

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