Submission #1340668

#	Time	Username	Problem	Language	Result	Execution time	Memory
1340668		justfady	Feast (NOI19_feast)	C++20	0 / 100	2 ms	344 KiB

feast

#include <bits/stdc++.h> //  +
using namespace std;     // +++
#define inf 1e18         //  +
#define int __int64_t
#define all(a) a.begin(), a.end()
void files() {
#ifndef ONLINE_JUDGE
    freopen("input.txt", "r", stdin), freopen("output.txt", "w", stdout);
#endif
}

int const N = 3e5 + 5;
pair<int, int> dp[N][2];
int vis[N][2], id;
int n, k, a[N], lamda;
pair<int, int> rec(int i, bool lst) {
    if (i == n) return {0, 0};
    auto &ret = dp[i][lst];
    if (vis[i][lst] == id) return ret;
    vis[i][lst] = id;
    auto leave = rec(i + 1, 0);
    auto take = rec(i + 1, 1);
    take.first += a[i];
    if (!lst) {
        take.first -= lamda;
        take.second--;
    }

    return ret = max(leave, take);
}

void solve() {
    cin >> n >> k;

    for (int i = 0; i < n; ++i) cin >> a[i];

    int st = 0, en = 1e16, md, ans = 0;
    while (st <= en) {
        md = (st + en) / 2;

        lamda = md;
        ++id;
        auto [d, cnt] = rec(0, 0);

        int used = -cnt;
        if (used > k) st = md + 1;
        else {
            ans = d + lamda * k;
            en = md - 1;
        }
    }
    cout << ans << '\n';
}

signed main() {
    ios_base::sync_with_stdio(0), cin.tie(0), cout.tie(0), files();
    int tc = 1;
    // cin >> tc;
    while (tc--)
        solve();
}

Compilation message (stderr)

feast.cpp: In function 'void files()':
feast.cpp:8:12: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)' declared with attribute 'warn_unused_result' [-Wunused-result]
    8 |     freopen("input.txt", "r", stdin), freopen("output.txt", "w", stdout);
      |     ~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~~
feast.cpp:8:46: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)' declared with attribute 'warn_unused_result' [-Wunused-result]
    8 |     freopen("input.txt", "r", stdin), freopen("output.txt", "w", stdout);
      |                                       ~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~~~~

• Subtask 1: 0 / 4
• Subtask 2: 0 / 8
• Subtask 3: 0 / 18
• Subtask 4: 0 / 10
• Subtask 5: 0 / 11
• Subtask 6: 0 / 20
• Subtask 7: 0 / 29