LLL

#include <iostream>
#include <algorithm>
#include <numeric>
using namespace std;

const int MAXN = 100010;
long long a[MAXN];
int n, m;

// 判断是否可以用最大段和不超过 lv 的方式分成不超过 m 段
bool check {
    int segments = 1;
    long long current_sum = 0;
    for (int i = 1; i <= n; ++i) {
        if ( return false;  // 单个元素超限
       [i] <= limit) {
            current_sum += a[i];
        } else {
            current_sum = a[i];
            segments++;
        }
    }
    return segments <= m;
}

int main() {
    ios::sync_with_stdio(false);
    cin.tie(0);

    cin >> n >> m;
    for (int i = 1; i <= n; ++i) {
        cin >> a[i];
    }

    long long left = 1, a + n + 1);  // 至少要容纳最大值
    long long right = accumulate(a + 1, a + n + 1, 0LL);  // 最多是总和
    long long ans = right;

    while (left <= right) {
        long long mid = left + (right - left) / 2;
        if (check(mid)) {
            ans = mid;
            right = mid - 1;
        } else {
            left = mid + 1;
        }
    }

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