Question 5 Rocky Bhai CPP Solution

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

    int main() {
           int t ;
           cin>>t ;
           while(t--){
           ll m,n,k ;
           cin>>m>>n>>k ;
           vector<ll>arr(m),brr(m) ;
           for(ll i=0;i<m;i++){
               cin>>arr[i] ;
           }
           for(ll j=0;j<m;j++){
               cin>>brr[j] ;
           }

           ll ans=0 ;
           ll st=0 , en=1e9 ;
           while(st<=en){
               ll mid=st+((en-st)/2) ;
              vector<ll> temp(m) ;
             for(int i=0;i<m;i++){
                ll a=((mid-arr[i])/brr[i])+1 ;
                if(mid<arr[i])temp[i]=0 ;
                else
                temp[i]=a ;
             }
             ll sum=0 ;
             sort(temp.begin(),temp.end(),greater<int>()) ;
             for(ll i=0;i<min(n,m);i++){
                 sum+=temp[i] ;
             }
             if(sum>=k){ans=mid ; en=mid-1 ;}
             else st=mid+1 ;
           }

           cout<<ans<<endl ;
    }
            return 0;
    }