Submission #1066873

#	Time	Username	Problem	Language	Result	Execution time	Memory
1066873		vjudge1	Building Bridges (CEOI17_building)	C++17	100 / 100	42 ms	15440 KiB

building

#include <bits/stdc++.h>
#define pb push_back
#define fi first
#define se second
#define pii pair<int, int>
#define pipii pair<int, pair<int, int>>
#define vi vector<int>
#define vpi vector<pair<int, int>>
#define ll long long
#define inp(name) if(fopen(name, "r")) freopen(name, "r", stdin);
#define out(name) if(fopen(name, "w")) freopen(name, "w", stdout);
const int N = 1e6 + 5;
const int mod = 1e9 + 7;
using namespace std;
long long n, h[N], w[N], s[N], dp[N];

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<>>
{
	static const ll inf = LLONG_MAX;
	ll div(ll a, ll b)
	{
		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;
	}
} LC;
int main()
{
    ios_base::sync_with_stdio(false);
    cin.tie(NULL);
    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];
        s[i] = s[i-1] + w[i];
    }

    dp[1] = -w[1];
    //LC.add(2*h[1], -h[1] * h[1]);

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

    cout << dp[n]+ s[n];
    return 0;
}

/*neu la kthuc 1 xau thi dat dp[u][1] = 0, k thi -inf, kqua la dp[1][k];*/

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