knapsack(fractional).txt

#include<bits/stdc++.h>
using namespace std;
#define ll long long

int main()
{
    ll n,m;
    cin>>n>>m;
    ll w[n],p[n];
    for(ll i=0;i<n;i++)
    {
        cin>>w[i];
    }
    for(ll i=0;i<n;i++)
    {
        cin>>p[i];
    }
    multimap<double,ll, greater<>> ma;
    for(ll i=0;i<n;i++)
    {
       ma.insert(make_pair(double(double(p[i])/double(w[i])), i));
    }
    for(auto itr=ma.begin();itr!=ma.end();itr++)
    {
        //cout<<itr->first<<" "<<itr->second<<endl;
    }
    double f[100]={0};
    for(auto itr=ma.begin();itr!=ma.end();itr++)
    {
        ll mini=min(m,w[itr->second]);
        m=m-mini;
        f[itr->second]=double(mini)/double(w[itr->second]);
        if(m==0)
        break;
    }
    double ans=0;
    for(ll i=0;i<n;i++)
    {
        //cout<<f[i]<<endl;
        ans+=p[i]*f[i];
    }
    cout<<ans<<endl;
}