Submission #1099485

#	Time	Username	Problem	Language	Result	Execution time	Memory
1099485		NoMercy	Discharging (NOI20_discharging)	C++14	100 / 100	87 ms	23952 KiB

Discharging

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

typedef long long ll;

const int MAXN = 1e6 + 55;

ll dp[MAXN], T[MAXN];

ll f (array<ll, 2> line, ll x) {
	return line[0] * x + line[1];
}
long double inters (array<ll, 2> line1, array<ll, 2> line2) {
	return (line2[1] - line1[1]) / (line1[0] - line2[0]);
}
struct Hull {
	deque<array<ll, 2>> dq;
	ll query (ll x) {
		while ((int)dq.size() > 1 && f(dq[0], x) > f(dq[1], x)) dq.pop_front();
		return f(dq[0], x);
	}
	void insert (array<ll, 2> line) {
		while (dq.size() > 1 && inters(line, dq.back()) <= inters(line, dq[dq.size() - 2])) dq.pop_back();
		dq.push_back(line);
	}
};

int32_t main () {

    ios_base::sync_with_stdio(0); 
    cin.tie(0); 
    cout.tie(0); 

    int N;
    cin >> N;
	for (int i = 1;i <= N;i ++) {
        cin >> T[i];
    }

    Hull hl;
	ll mx = 1, ind = 1;
	for (int i = 1;i <= N;i ++) {
		if (T[i] >= T[mx]) {
            mx = i;
        }
		while (ind <= mx){
			hl.insert({-1LL * ind, dp[ind - 1]});
			ind ++;
		}
		if (i > 1) {
            dp[i] = min(T[mx] * N, hl.query(T[mx]) + T[mx] * (N + 1));
        } else {
            dp[i] = T[1] * N;
        }
	}
	cout << dp[N] << "\n";
}

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