Profu

#include <fstream>
#define NMAX 500001

using namespace std;

long long int A[NMAX],n,k,C,s,maxim;

ifstream in("profu.in");
ofstream out("profu.out");

long long int CalcTransport(long long int ip)
{
    long long int trans,i,cap;
    i=1;
    cap=trans=0;
    while(i<=n)
    {
        if(cap+A[i]<=ip)
        {
            cap+=A[i];
            i++;
        }
        else
        {
            trans++;
            cap=0;
        }
    }
    if(cap==0)
        return trans;
    return trans+1;
}


long long int CautBinar()
{
    long long int p,u,m,rez;
    p=maxim;
    u=s;
    while(p<=u)
    {
        m=p+(u-p)/2;
        if(CalcTransport(m)<=k)
        {
            rez=m;
            u=m-1;
        }
        else
            p=m+1;
    }
    return rez;
}

void Citire()
{
    in>>n>>k;
    for(long long int i=1; i<=n; i++)
    {
        in>>A[i];
        if(A[i]>maxim)
            maxim=A[i];
        s+=A[i];
    }
}

int main()
{
    Citire();
    out<<CautBinar();
    return 0;
}