Submission #1110896

#	Time	Username	Problem	Language	Result	Execution time	Memory
1110896		DylanSmith	Feast (NOI19_feast)	C++17	100 / 100	112 ms	4608 KiB

feast

#include <bits/stdc++.h>

using namespace std;

typedef long long ll;

#define pb push_back
#define sz(x) (int)x.size()
#define all(x) begin(x),end(x)
#define lb(x,y) lower_bound(all(x),y)-begin(x)

mt19937 rng;

pair<ll, int> check(vector<int> &a, ll cost) {
    pair<ll, int> n = {0, 0}, y = {LLONG_MIN, 0};
    for (int i = 0; i < sz(a); i++) {
        pair<ll, int> n2 = n;
        if (y.first != LLONG_MIN) n2 = max(n2, y);
        pair<ll, int> y2 = {n.first + a[i] - cost, n.second + 1};
        if (y.first != LLONG_MIN) {
            y2 = max(y2, {y.first + a[i], y.second});
            y2 = max(y2, {y.first + a[i] - cost, y.second + 1});
        }
        swap(n, n2);
        swap(y, y2);
    }
    auto res = max(n, y);
    if (cost == 0) res.second = sz(a);
    return res;
}

ll search(vector<int> &a, int K, ll l, ll r) {
    if (l > r) return LLONG_MIN;
    ll mid = (l + r) / 2;
    auto p = check(a, mid);
    if (p.second >= K) {
        ll m = search(a, K, mid + 1, r);
        if (m != LLONG_MIN) return m;
        return p.first + K * mid;
    }
    return search(a, K, l, mid - 1);
}

void solve() {
    int N, K; cin >> N >> K;
    vector<int> a(N);
    for (int i = 0; i < a.size(); i++) cin >> a[i];
    cout << search(a, K, 0, LLONG_MAX / 2) << "\n";
}

int main() {
    ios::sync_with_stdio(false);
    cin.tie(nullptr);
    rng = mt19937(chrono::steady_clock::now().time_since_epoch().count());

    solve();

    return 0;
}

Compilation message (stderr)

feast.cpp: In function 'void solve()':
feast.cpp:47:23: warning: comparison of integer expressions of different signedness: 'int' and 'std::vector<int>::size_type' {aka 'long unsigned int'} [-Wsign-compare]
   47 |     for (int i = 0; i < a.size(); i++) cin >> a[i];
      |                     ~~^~~~~~~~~~

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