제출 #543238

#	제출 시각	아이디	문제	언어	결과	실행 시간	메모리
543238		fcw	Building Bridges (CEOI17_building)	C++17	100 / 100	51 ms	10588 KiB

building

#include <bits/stdc++.h>
#define st first
#define nd second
using lint = int64_t;
constexpr int mod = int(1e9) + 7;
constexpr int inf = 0x3f3f3f3f;
constexpr int ninf = 0xcfcfcfcf;
constexpr lint linf = 0x3f3f3f3f3f3f3f3f;
const long double pi = acosl(-1.0);
// Returns -1 if a < b, 0 if a = b and 1 if a > b.
int cmp_double(double a, double b = 0, double eps = 1e-9) {
	return a + eps > b ? b + eps > a ? 0 : 1 : -1;
}
using namespace std;

struct Line {
	mutable lint k, m, p;
	bool operator<(const Line& o) const { return k < o.k; }
	bool operator<(lint x) const { return p < x; }
};
struct LineContainer : multiset<Line, less<>> {
	// (for doubles, use inf = 1/.0, div(a,b) = a/b)
	static const lint inf = LLONG_MAX;
	lint div(lint a, lint b) { // floored division
		return a / b - ((a ^ b) < 0 && a % b); }
	bool isect(iterator x, iterator y) {
		if (y == end()) { x->p = inf; return false; }
		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(lint k, lint 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));
	}
	lint query(lint x) {
		assert(!empty());
		auto l = *lower_bound(x);
		return l.k * x + l.m;
	}
};

int main() {
	cin.tie(nullptr)->sync_with_stdio(false);
	int n;
	cin>>n;
	vector<lint>h(n), w(n);
	for(int i=0;i<n;i++) cin>>h[i];
	for(int i=0;i<n;i++) cin>>w[i];
	vector<lint>pref(n+1);
	for(int i=0;i<n;i++) pref[i+1] = pref[i] + w[i];
	LineContainer g;
	g.add(2 * h[0], -h[0] * h[0] + pref[1]);
	vector<lint>dp(n);
	for(int i=1;i<n;i++){
		dp[i] = h[i] * h[i] + pref[i] - g.query(h[i]);
		g.add(2 * h[i], -h[i] * h[i] + pref[i+1] - dp[i]);
	}
	cout<<dp[n-1]<<"\n";
	
	return 0;
}
/*
[  ]Leu o problema certo???
[  ]Ver se precisa de long long
[  ]Viu o limite dos fors (é n? é m?)
[  ]Tamanho do vetor, será que é 2e5 em vez de 1e5??
[  ]Testar sample
[  ]Testar casos de  borda
[  ]1LL no 1LL << i
[  ]Testar mod (é 1e9+7, mesmo?, será que o mod não ficou negativo?)
*/

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