Submission #435540

#	Time	Username	Problem	Language	Result	Execution time	Memory
435540		meatrow	Discharging (NOI20_discharging)	C++17	100 / 100	222 ms	17980 KiB

Discharging

#include <bits/stdc++.h>
 
using namespace std;
 
using ll = long long;
using ld = long double;
 
const int MOD = 998244353;
 
ll binpow(ll a, ll p, int mod = MOD) {
    ll res = 1;
    while (p) {
        if (p & 1) {
            (res *= a) %= mod;
        }
        p >>= 1;
        (a *= a) %= mod;
    }
    return res;
}
 
ll gcd(ll a, ll b) {
    return b == 0 ? a : gcd(b, a % b);
}

struct Line {
	mutable ll k, m, p;
	bool operator<(const Line& o) const { return k < o.k; }
	bool operator<(ll x) const { return p < x; }
};

struct LineContainer : multiset<Line, less<>> {
	// (for doubles, use inf = 1/.0, div(a,b) = a/b)
	static const ll inf = LLONG_MAX;
	ll div(ll a, ll b) { // floored division
		return a / b - ((a ^ b) < 0 && a % b); }
	bool isect(iterator x, iterator y) {
		if (y == end()) return x->p = inf, 0;
		if (x->k == y->k) x->p = x->m > y->m ? inf : -inf;
		else x->p = div(y->m - x->m, x->k - y->k);
		return x->p >= y->p;
	}
	void add(ll k, ll m) {
		auto z = insert({k, m, 0}), y = z++, x = y;
		while (isect(y, z)) z = erase(z);
		if (x != begin() && isect(--x, y)) isect(x, y = erase(y));
		while ((y = x) != begin() && (--x)->p >= y->p)
			isect(x, erase(y));
	}
	ll query(ll x) {
		assert(!empty());
		auto l = *lower_bound(x);
		return l.k * x + l.m;
	}
};

void solve() {
    int n;
    cin >> n;
    vector<ll> dp(n);
    LineContainer cht;
    cht.add(-n, 0);
    ll mx = 0;
    for (int i = 0; i < n; i++) {
        ll t;
        cin >> t;
        mx = max(mx, t);
        dp[i] = cht.query(mx);
        cht.add(-n + i + 1, dp[i]);
    }
    cout << -dp[n - 1] << endl; 
}
 
int main() {
    ios::sync_with_stdio(false);
    cin.tie(nullptr);
    int T = 1;
    // cin >> T;
    for (int tc = 1; tc <= T; tc++) {
        // cout << "Case #" << tc << ": ";
        solve();
    }
    return 0;
}

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