OI-codes/Luogu/problem/P1182/P1182.cpp

#include <bits/stdc++.h>

using namespace std;

int n, m, a[100005], l, r, mid, ans;

bool check(int x) {
    int tot = 0, num = 0;
    for (int i = 1; i <= n; i++) {
        if (tot + a[i] <= x) {
            tot += a[i];
        }
        else {
            tot = a[i];
            num++;
        }
    }
    return num >= m;
}
int main() {
    cin >> n >> m;
    for (int i = 1; i <= n; i++) {
        cin >> a[i];
        l = max(l, a[i]);
        r += a[i];
    }
    while (l <= r) {
        mid = l + r >> 1;
        if (check(mid)) {
            l = mid + 1;
        }
        else {
            r = mid - 1;
        }
    }
    cout << l << endl;
    return 0;
}