UVa 10325 - The Lottery

http://uva.onlinejudge.org/index.php?option=com_onlinejudge&Itemid=8&page=show_problem&category=15&problem=1266&mosmsg=Submission+received+with+ID+11830997

容斥原理 第一题  水！

代码：

#include<iostream>

#include<cstring>

#include<cstdio>

#include<string>

#include<set>

#include<map>

#include<cmath>

#include<algorithm>

#include<vector>

#include<cmath>

#include<queue>

#include<stack>



//#define ull unsigned long long

#define ll long long



using namespace std;



const int INF=0x3f3f3f3f;

const int MOD=1000000007;

const double eps=1e-6;

const int N=50;

ll gcd(ll x,ll y)

{

    if(x%y==0)

    return y;

    return gcd(y,x%y);

}

ll lcm(ll x,ll y)

{

    return x*y/gcd(x,y);

}

ll a[N];

ll solve(ll *a,int n,ll M)

{

    ll sum=0;

    for(int k=1;k<(1<<n);++k)

    {

        ll LCM=1;

        int num=0;

        for(int i=0;i<n;++i)

        {

            if(k&(1<<i))

            {

                ++num;

                LCM=lcm(LCM,a[i]);

            }

        }

        if((num&1)==1)

        {

            sum+=(M/LCM);

        }else

        {

            sum-=(M/LCM);

        }

    }

    return sum;

}

int main()

{

    //freopen("data.in","r",stdin);

    ll n;

    int m;

    while(cin>>n>>m)

    {

        for(int i=0;i<m;++i)

        cin>>a[i];

        cout<<(n-solve(a,m,n))<<endl;

    }

    return 0;

}