wa#4求条

#include<bits/stdc++.h>
using namespace std;
#define int long long
#define endl '\n'
const int N = 1e5 + 10;
int a[N];
int n,k;
bool pd(int m){
    int cnt = 0;
    int p = 0;
    for(int i = 1;i <= n;i ++){
        if(a[i] + p <= m)p += a[i];
        else p = a[i],cnt ++;
    }
    return cnt >= k;
}
signed main(){
    ios::sync_with_stdio(0);
    cin.tie(0);cout.tie(0);
    cin >> n >> k;
    int sum = 0;
    int ma = -1;
    for(int i = 1;i <= n;i ++){
        cin >> a[i];
        sum += a[i];
        ma = max(ma,a[i]);
    }
    int l = ma,r = sum;
    while(l + 1 < r){
        int m = l + r >> 1;
        if(pd(m))l = m;
        else r = m;
    }
    cout << r << endl;
    return 0;
}