Submission #1078640

#	Time	Username	Problem	Language	Result	Execution time	Memory
1078640		YudoTLE	Feast (NOI19_feast)	C++17	100 / 100	102 ms	12832 KiB

feast

#include <bits/stdc++.h>
using namespace std;

using ll = long long;
using pll = pair<ll, ll>;

const ll INF = LLONG_MAX / 2;
const int iINF = INT_MAX / 2;
const int MAXN = 3e5 + 5;

int n, k;
ll arr[MAXN], dp[MAXN][2];
int cnt[MAXN][2];

pll eval(ll c)
{
    dp[0][1] = -INF;
    for (int i = 1; i <= n; i++)
    {
        if (dp[i - 1][0] >= dp[i - 1][1])
        {
            dp[i][0] = dp[i - 1][0];
            cnt[i][0] = cnt[i - 1][0];
        }
        else
        {
            dp[i][0] = dp[i - 1][1];
            cnt[i][0] = cnt[i - 1][1];
        }
        if (dp[i - 1][0] - c >= dp[i - 1][1])
        {
            dp[i][1] = arr[i] + dp[i - 1][0] - c;
            cnt[i][1] = cnt[i - 1][0] + 1;
        }
        else
        {
            dp[i][1] = arr[i] + dp[i - 1][1];
            cnt[i][1] = cnt[i - 1][1];
        }
    }
    return max(pll(dp[n][0], cnt[n][0]), pll(dp[n][1], cnt[n][1]));
}

void solve()
{
    cin >> n >> k;
    for (int i = 1; i <= n; i++)
        cin >> arr[i];

    ll answer = 0;
    ll lo = 0, hi = INF;
    while (lo <= hi)
    {
        ll mi = lo + (hi - lo) / 2;
        auto [optv, optc] = eval(mi);
        if (optc <= k)
            hi = mi - 1, answer = max(answer, optv + optc * mi);
        else
            lo = mi + 1;
    }

    cout << answer << '\n';
}

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

    int t = 1;
    // cin >> t;
    while (t--) solve();

    return 0;
}

• 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