Submission #1047171

#	Time	Username	Problem	Language	Result	Execution time	Memory
1047171		Sharky	Split the sequence (APIO14_sequence)	C++17	0 / 100	13 ms	4952 KiB

sequence

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

#define int long long
using db = long double;
const int maxn = 1E5+5;
int n, K, l = 1, r = 1, a[maxn], p[maxn], Q[maxn], bk[maxn];
vector<int> dp, new_dp;

bool m(int j, int k, int i) {
    return ((dp[k] - dp[j]) * (p[i] - p[k])) <= ((dp[i] - dp[k]) * (p[k] - p[j]));
}

bool idk(int j, int k, int i) {
    return (p[n] - p[i]) * (p[k] - p[j]) <= (dp[k] - dp[j]);
}

int32_t main() {
    cin >> n >> K;
    new_dp.assign(n+1, 0);
    dp.assign(n+1, 0);
    for (int i = 1; i <= n; i++) {
        cin >> a[i];
        p[i] = p[i-1] + a[i];
    }
    for (int i = 1; i <= n; i++) {
        dp[i] = p[i] * (p[n] - p[i]);
    }
    for (int kk = 2; kk <= K; kk++) {
        for (int i = 1; i <= n; i++) Q[i] = 0;
        for (int i = n; i >= 1; i--) new_dp[i] = dp[i];
        l = r = 1;
        for (int i = 1; i < kk; i++) Q[r++] = i;
        --r;
        for (int i = kk; i <= n; i++) {
            while (r - l >= 1 && idk(Q[l], Q[l+1], i)) l++;
            if (l <= r) {
                new_dp[i] = dp[Q[l]] + (p[i] - p[Q[l]]) * (p[n] - p[i]);
                bk[i] = Q[l];
            }
            while (r - l >= 1 && m(Q[r-1], Q[r], i)) r--;
            r++; Q[r] = i;
        }
        swap(new_dp, dp);
    }
    int stupid = n;
    vector<int> pth;
    K++;
    while (K--) {
        pth.push_back(stupid);
        stupid = bk[stupid];
    }
    cout << *max_element(dp.begin(), dp.end()) << '\n';
    reverse(pth.begin(), pth.end());
    pth.pop_back();
    for (auto x : pth) cout << x << ' ';
    cout << '\n';
}

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