제출 #841818

#	제출 시각	아이디	문제	언어	결과	실행 시간	메모리
841818		WLZ	Building Bridges (CEOI17_building)	C++17	100 / 100	46 ms	10072 KiB

building

#include <bits/stdc++.h>
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;
	}
};
 
 
int main() {
  ios::sync_with_stdio(false);
  cin.tie(0);
  int n;
  cin >> n;
  vector<long long> h(n + 1), w(n + 1, 0);
  for (int i = 1; i <= n; i++) cin >> h[i];
  for (int i = 1; i <= n; i++) cin >> w[i], w[i] += w[i - 1];
  vector<long long> dp(n + 1, 0);
  LineContainer cht;
  for (int i = 1; i <= n; i++) {
    if (i > 1) dp[i] = -cht.query(h[i]) + w[i - 1] + h[i] * h[i];
    cht.add(2ll * h[i], -(dp[i] - w[i] + h[i] * h[i]));
  }
  cout << dp[n] << '\n';
  return 0;
}

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