Submission #573581

#	Time	Username	Problem	Language	Result	Execution time	Memory
573581		danikoynov	Feast (NOI19_feast)	C++14	0 / 100	1096 ms	5764 KiB

feast

/**
 ____ ____ ____ ____ ____ ____
||l |||e |||i |||n |||a |||d ||
||__|||__|||__|||__|||__|||__||
|/__\|/__\|/__\|/__\|/__\|/__\|

**/

#include<bits/stdc++.h>
#define endl '\n'

using namespace std;
typedef long long ll;

void speed()
{
    ios_base::sync_with_stdio(false);
    cin.tie(NULL);
    cout.tie(NULL);
}

const int maxn = 3e5 + 10;

int n;
ll k, a[maxn], dp[maxn], cnt[maxn], par[maxn];

pair < ll, int > calc(ll cost)
{
    for (int i = 1; i <= n; i ++)
    {
        dp[i] = dp[i - 1];
        cnt[i] = cnt[i - 1];
        for (int j = 1; j <= i; j ++)
        {
            ll sum = dp[j - 1] - cost + par[i] - par[j - 1];
            if (sum > dp[i])
                dp[i] = sum;
            if (sum == dp[i])
                cnt[i] = max(cnt[i], cnt[j - 1] + 1);
        }
    }
    pair < ll, int > ans = {dp[1], cnt[1]};
    for (int i = 2; i <= n; i ++)
        if (make_pair((ll)dp[i], (int)cnt[i]) > ans)
            ans = {dp[i], cnt[i]};
    return ans;
}
void solve()
{
    cin >> n >> k;

    ll cnt = 0;
    for (int i = 1; i <= n; i ++)
    {
        cin >> a[i];
        if (a[i] >= 0)
            cnt ++;
        par[i] = par[i - 1] + a[i];
    }
    k = min(cnt, k);

    ll lf = 0, rf = 1e12;
    while(lf <= rf)
    {
        ll mf = (lf + rf) / 2;
        pair < double, int > cur = calc(mf);
        if (cur.second >= k)
            lf = mf + 1;
        else
            rf = mf - 1;
    }

    double p1 = lf - 1, p2 = lf;
    pair < ll, int > cur1 = calc(p1), cur2 = calc(p2);
    cur1.first = cur1.first + cur1.second * p1;
    cur2.first = cur2.first + cur2.second * p2;
    double part = 1.0 - (double)(cur1.second - k) / (double)(cur1.second - cur2.second);
    double slope = (cur1.first - cur2.first);
    double ans = cur2.first + slope * part;
    ///cout << cur1.second << " " << cur2.second << " " << part << " " << cur1.second - k << " " << k << endl;
    if (cur1.second == 1 && cur2.second == 0)
    {

        cout << cur1.first << endl;
        return;
    }
    if (cur1.second == cur2.second)
    {
        cout << cur1.first << endl;
        return;
    }
    cout << round(ans) << endl;
}

int main()
{
    solve();
    return 0;
}
/**
7 1
3 4 -1 2 3 -5 1
*/

• 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