Array Division (CSES)

#include <iostream>
#include <vector>
#include <algorithm>
#include <numeric>
#include <cmath>
#include <queue>
using namespace std;
const int N = 2e5;
long long a[N+1], n, k;
void read()
{
   cin >> n >> k;
   for (int i = 1; i <= n; ++ i)
   {
       cin >> a[i];
   }
}
bool check(long long x)
{
    int cnt = 0, cur = 1;
    while (cnt < k && cur <= n)
    {
        long long sum = 0;
        while (cur <= n && sum + a[cur] <= x)
        {
            sum += a[cur];
            ++cur;
        }
        ++cnt;
    }
    return cur == n + 1;
}
void solve()
{
   long long low = 0, high = 1e18;
   while (low <= high)
   {
       long long mid = (low + high)/2;
       if (check(mid))
       {
           high = mid - 1;
       }
       else
       {
           low = mid + 1;
       }
   }
   cout << low;
}
int main()
{
    ios_base::sync_with_stdio(false);
    cin.tie(nullptr);
    read();
    solve();
}