Submission #1066791

#	Time	Username	Problem	Language	Result	Execution time	Memory
1066791		vjudge1	Building Bridges (CEOI17_building)	C++14	100 / 100	41 ms	9760 KiB

building

//    Tiger II H my beloved    //
#include <bits/stdc++.h>
#define ll long long
using namespace std;
const int N = 1e5 + 16;
long long n, dp[N], h[N], w[N], k, sum = 0;
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;
	}
};
LineContainer e;
int main () {
    ios_base::sync_with_stdio (0);
    cin.tie (0);
    cout.tie (0);

    cin>>n;
    for (int i = 1; i <= n; i ++)
    {
        cin>>h[i];
    }
    for (int i = 1; i <= n; i ++)
    {
        cin>>w[i];
    }
    dp[1] = -w[1];
    for (int i = 2; i <= n; i ++)
    {
        e.add (2 * h[i - 1], - h[i - 1] * h[i - 1] - dp[i - 1]);
        dp[i] = -e.query (h[i]) + h[i] * h[i] - w[i];
    }
    for (int i = 1; i <= n; i ++)
    {
        sum += w[i];
    }
    cout<<dp[n] + sum;

    return 0;
}

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