Submission #928000

#	Time	Username	Problem	Language	Result	Execution time	Memory
928000		HiepVu217	Split the sequence (APIO14_sequence)	C++17	62 / 100	459 ms	86924 KiB

sequence

#include <bits/stdc++.h>
using namespace std;
const int N = 1e5 + 17;
int n, k, cut[217][N], z, as[N], c, it, sz;
long long a[N], f[N], fz[N], s[N], ans;
struct line
{
    long long a, b;
    int c;
} l, cv[N];
bool bad (line l1, line l2, line l3)
{
    return 1.0 * (l1.b - l3.b) / (l3.a - l1.a) > 1.0 * (l1.b - l2.b) / (l2.a - l1.a);
}
long long calc (long long x, int i, int j)
{
    while (it < sz)
    {
        if (cv[it].a * x + cv[it].b > cv[it + 1].a * x + cv[it + 1].b)
        {
            break;
        }
        ++it;
    }
    cut[j][i] = cv[it].c;
    return cv[it].a * x + cv[it].b;
}
int main()
{
    ios_base::sync_with_stdio(0);
    cin.tie(0);
    cout.tie(0);
    cin >> n >> k;
    for (int i = 1; i <= n; ++i)
    {
        cin >> a[i];
        s[i] = s[i - 1] + a[i];
    }
    for (int j = 2; j <= k + 1; ++j)
    {
        sz = 0, it = 1;
        for (int i = j - 2; i < n; ++i)
        {
            l = {-s[i - 1], fz[i - 1], i - 1};
            fz[i - 1] = f[i - 1];
            while (sz > 1)
            {
                if (bad (cv[sz - 1], cv[sz], l))
                {
                    --sz;
                    continue;
                }
                break;
            }
            it = max (1, min (it, sz));
            cv[++sz] = l;
            f[i] = calc (s[n] - s[i], i, j - 1) + s[i] * (s[n] - s[i]);
            if (f[i] >= ans)
            {
                ans = f[i];
                z = i;
            }
        }
    }
    cout << ans << "\n";
    if (!z)
    {
        return 0;
    }
    as[++c] = z;
    int x = cut[k][z];
    while (k - 1)
    {
        as[++c] = x;
        x = cut[--k][x];
    }
    while (c--)
    {
        cout << as[c + 1] << " ";
    }
}

• Subtask 1: 11 / 11
• Subtask 2: 11 / 11
• Subtask 3: 11 / 11
• Subtask 4: 0 / 17
• Subtask 5: 0 / 21
• Subtask 6: 29 / 29