2025-09-12 14:50:25 -03:00

124 lines
2.6 KiB
C++

/* Problem URL: https://codeforces.com/edu/course/2/lesson/6/2/practice/contest/283932/problem/G */
#include <bits/stdc++.h>
#include <ext/pb_ds/assoc_container.hpp>
#include <ext/pb_ds/tree_policy.hpp>
using namespace std;
using namespace __gnu_pbds;
template <class T, class comp = less<>>
using ordered_set = tree<T, null_type , comp , rb_tree_tag , tree_order_statistics_node_update>;
#define V vector
#define rmin(a, b) a = min(a, b)
#define rmax(a, b) a = max(a, b)
#define rep(i, lim) for (int i = 0; i < (lim); i++)
#define nrep(i, s, lim) for (int i = s; i < (lim); i++)
#define repv(i, v) for (auto &i : (v))
#define fillv(v) for (auto &itr_ : (v)) { cin >> itr_; }
#define sortv(v) sort(v.begin(), v.end())
#define all(v) (v).begin(), (v).end()
using vi = vector<int>;
using vvi = vector<vi>;
using vvvi = vector<vvi>;
using vvvvi = vector<vvvi>;
using ll = long long;
using vl = vector<ll>;
using vvl = vector<vl>;
using vvvl = vector<vvl>;
using vvvvl = vector<vvvl>;
template<class v>
auto operator<<(ostream &os, const vector<v> &vec)->ostream& {
os << vec[0];
for (size_t i = 1; i < vec.size(); i++) {
os << ' ' << vec[i];
}
os << '\n';
return os;
}
template<class v>
auto operator>>(istream &is, vector<v> &vec)->istream& {
for (auto &i : vec) {
is >> i;
}
return is;
}
template<class v>
auto operator<<(ostream &os, const vector<vector<v>> &vec)->ostream& {
for (auto &i : vec) {
os << i[0];
for (size_t j = 1; j < i.size(); j++) {
os << ' ' << i[j];
}
os << '\n';
}
return os;
}
template<class v>
auto operator>>(istream &is, vector<vector<v>> &vec)->istream& {
for (auto &i : vec) {
for (auto &j : i) {
is >> j;
}
}
return is;
}
int main()
{
ios::sync_with_stdio(false);
cin.tie(nullptr);
int k, n;
cin >> k >> n;
vl fds(n);
cin >> fds;
ll ans = 0;
ll low = 0;
ll high = INT64_MAX >> 1;
while (low <= high) {
ll mid = (high + low) >> 1;
vvl dp(n, vl(k + 1));
dp[0][1] = min(fds[0], mid);
dp[0][0] = mid - dp[0][1];
nrep(i, 1, n) {
ll now = fds[i];
rep(j, k) {
ll minimal = min(dp[i - 1][j], now);
dp[i][j + 1] += minimal;
dp[i][j] += dp[i - 1][j] - minimal;
now -= minimal;
}
dp[i][k] += dp[i - 1][k];
}
if (dp.back().back() >= mid) {
ans = mid;
low = mid + 1;
continue;
}
high = mid - 1;
}
cout << ans << '\n';
}