Submission #995333

#	Time	Username	Problem	Language	Result	Execution time	Memory
995333		vyshniak_n	Discharging (NOI20_discharging)	C++17	100 / 100	112 ms	25728 KiB

Discharging

//#pragma optimize("Ofast")
//#pragma optimize("unroll-loops")
//#pragma traget("avx,avx2")

#include <iostream>
#include <cmath>
#include <algorithm>
#include <stdio.h>
#include <cstdint>
#include <cstring>
#include <string>
#include <cstdlib>
#include <vector>
#include <bitset>
#include <map>
#include <queue>
#include <ctime>
#include <stack>
#include <set>
#include <list>
#include <random>
#include <deque>
#include <functional>
#include <iomanip>
#include <sstream>
#include <fstream>
#include <complex>
#include <numeric>
#include <cassert>
#include <array>
#include <tuple>
#include <unordered_map>
#include <unordered_set>
#include <thread>

typedef long long ll;
typedef unsigned long long ull;
typedef long double ld;

#define el '\n'
#define ff first
#define ss second
#define pb push_back
#define pf push_front
#define popb pop_back
#define popf pop_front
#define point pair <ll, ll>
#define all(x) x.begin(), x.end()
#define rall(x) x.rbegin(), x.rend()

using namespace std;

#include <random>
mt19937 rnd(time(0));

const ll INF = 1e18 + 10;
const ll inf = 1e9 + 10;
const ll N = 1e6 + 10;
const ll mod = 1e9 + 7;
const ll LOG = 20;
const ll K = 1e3 + 20;

struct line {
    ll k, b;
};

vector <ld> dots;
vector <line> dq;
ll dp[N], t[N];

ld cross(line l, line r) {
    return (ld)(r.b - l.b) / (ld)(l.k - r.k);
}
void add(line x) {
    while (dq.size() >= 2 && cross(x, dq[dq.size() - 2]) <= cross(dq[dq.size() - 1], dq[dq.size() - 2])) {
        dots.popb();
        dq.popb();
    }

    if (!dq.empty())
        dots.pb(cross(dq.back(), x));
    dq.pb(x);
}
ll get(ll x) {
    if (dots.empty())
        return dq[0].k * x + dq[0].b;

    ll l = -1, r = dots.size();
    while (l + 1 < r) {
        ll mid = (l + r) >> 1;

        if (dots[mid] <= x) l = mid;
        else r = mid;
    }

    l++;
    return dq[l].k * x + dq[l].b;
}

void solve() {
    ll n;
    cin >> n;

    for (ll i = 1; i <= n; i++)
        cin >> t[i];

    add({n, dp[0]});
    ll mx = 0;
    for (ll i = 1; i <= n; i++) {
        mx = max(mx, t[i]);
        dp[i] = get(mx);
        add({n - i, dp[i]});
    }

    cout << dp[n] << el;
    return;
}
signed main() {
    ios_base::sync_with_stdio(0);
    cin.tie(0); cout.tie(0);

    int tests = 1;
    //cin >> tests;

    while (tests--) 
        solve();
    return 0;
}
/*
kx + b = k1x + b1;
kx - k1x = b1 - b;
x = b1 - b

*/

• Subtask 1: 9 / 9
• Subtask 2: 13 / 13
• Subtask 3: 25 / 25
• Subtask 4: 11 / 11
• Subtask 5: 14 / 14
• Subtask 6: 28 / 28