Frequent Subsets Problem 进制运算 2017 ACM-ICPC 亚洲区（南宁赛区）网络赛

题目链接

因为n只到20,直接利用二进制的位运算暴力解决,1代表有该元素,0代表没有该元素

#include<bits/stdc++.h>using namespace std;typedef long long ll;int n;double m;stringstream ss;string s;int t;int c[55];int sum=0;int main(){//    freopen("data.txt","r",stdin);    ios_base::sync_with_stdio(false);    memset(c,0,sizeof(c));    getline(cin,s);    ss<<s;    ss>>n>>m;    while(getline(cin,s))    {        ss.clear();        ss<<s;        while(ss >> t)        {            c[sum] |= ( 1<<(t-1) );        }//        cout <<c[sum]<<endl;        sum++;    }    int xx = ceil(m*sum);    int ans = 0;    int maxx = (1<<n);    for(int i=1;i<=maxx;i++)    {        int ct = 0;        for(int j=0;j<sum;j++)        {            if((i&c[j])==i)            {//                cout <<(i&c[j])<<" "<<i<<endl;                ct++;            }        }//        if(ct)cout<<ct<<endl;        if(ct>=xx) ans++;    }    cout<<ans<<endl;    return 0;}