Submission #1180502

#	Time	Username	Problem	Language	Result	Execution time	Memory
1180502		rastervc	Building Bridges (CEOI17_building)	C++20	60 / 100	44 ms	8260 KiB

building

#include <bits/stdc++.h>
#define int long long

using namespace std;

using ll = long long;

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;
	}
};

signed main() {
    ios_base::sync_with_stdio(false);
    cin.tie(nullptr);

    int N;
    cin >> N;

    vector<int> h(N), w(N);
    for (int &x : h) cin >> x;
    for (int &x : w) cin >> x;

    int sum = accumulate(w.begin(), w.end(), 0), dp = 0;
    LineContainer lines;

    lines.add(2 * h[0], w[0] - h[0] * h[0]);
    for (int i = 1; i < N; ++i) {
        dp = -w[i] + h[i] * h[i] - lines.query(h[i]);
        lines.add(2 * h[i], -dp - h[i] * h[i]);
    }

    cout << sum + dp;

    return 0;
}

• Subtask 1: 30 / 30
• Subtask 2: 30 / 30
• Subtask 3: 0 / 40