제출 #95808

#	제출 시각	아이디	문제	언어	결과	실행 시간	메모리
95808		fedoseevtimofey	수열 (APIO14_sequence)	C++14	100 / 100	644 ms	84148 KiB

sequence

#include <bits/stdc++.h>
 
using namespace std;
 
typedef long long ll;
typedef long double ld;
 
struct line {
    ll k, b;
    line (ll k, ll b) : k(k), b(b) {}
};
 
ll f(const line &l, ll x) {
    return l.k * x + l.b;
}
 
ld inter(const line &a, const line &b) {
    return (ld)(a.b - b.b) / (b.k - a.k);
}
 
vector <line> s;
vector <int> idx;

int ptr = 0;
 
void push(const line &l, int id) {
    while ((int)s.size() && s[(int)s.size() - 1].k == l.k && s[(int)s.size() - 1].b <= l.b) {
        s.pop_back();
        idx.pop_back();
    }
    if (!s.empty() && s.back().k == l.k && s.back().b > l.b) return;
    while ((int)s.size() >= 2) {
        line a = s[(int)s.size() - 1];
        line b = s[(int)s.size() - 2];
        if (inter(l, a) <= inter(l, b)) {
            s.pop_back();
            idx.pop_back();
        }
        else {
            break;
        }
    }
    s.push_back(l);
    idx.push_back(id);
}
 
pair <ll, int> get(ll x) {
    ptr = min(ptr, (int)s.size() - 1);
    while (ptr + 1 < (int)s.size() && f(s[ptr], x) <= f(s[ptr + 1], x)) ++ptr;
    return {f(s[ptr], x), idx[ptr]};
}
 
 
const ll Inf = 2e18;
 
int main() {
    ios_base::sync_with_stdio(false); cin.tie(0); cout.setf(ios::fixed); cout.precision(20);
    #ifdef LOCAL
    freopen("input.txt", "r", stdin);
    freopen("output.txt", "w", stdout);
    #endif
    int n, k;
    cin >> n >> k;
    vector <int> a(n);
    for (int i = 0; i < n; ++i) {
        cin >> a[i];
    }
    vector <ll> dp(n + 1, -Inf);
    dp[0] = 0;
    vector <ll> pref(n + 1);
    for (int i = 0; i < n; ++i) {
        pref[i + 1] = pref[i] + a[i];
    }
    vector <vector <int>> who(k + 1, vector <int> (n + 1, -1));
    for (int j = 1; j <= k; ++j) {
        ptr = 0;
        s.clear();
        idx.clear();
        push(line(pref[0], -pref[0] * pref[n] + dp[0]), 0);
        dp[0] = -Inf;
        for (int i = 1; i <= n; ++i) {
            auto p = get(pref[i]);
            push(line(pref[i], -pref[i] * pref[n] + dp[i]), i);
            dp[i] = p.first + pref[i] * (pref[n] - pref[i]);
            who[j][i] = p.second;
        }
    }
    ll ans = -1;
    int id = -1;
    for (int i = 1; i < n; ++i) {
        if (dp[i] > ans) {
            ans = dp[i];
            id = i;
        }
    }

    vector <int> where;
    for (int cr = k; cr >= 1; --cr) {
        where.push_back(id);
        id = who[cr][id];
    }
    reverse(where.begin(), where.end());
    cout << ans << '\n';
    for (auto x : where) {
        cout << x << ' ';
    }
}

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