Submission #870469

#	Time	Username	Problem	Language	Result	Execution time	Memory
870469		_no_name	Building Bridges (CEOI17_building)	C++17	30 / 100	22 ms	9052 KiB

building

//Ai_2007
//Make the impossible possible
#include<bits/stdc++.h>
#define ll long long
#define fo(i,m,n) for(int i=m; i<=n; i++)
#define fod(i,m,n) for(int i=m; i>=n; i--)
#define fi first
#define se second
#define Nmax 1000001
#define pb push_back
#define pii pair<int,int>
using namespace std;
const int maxn=1e6+5;
const ll INFL=1e18;
int n,h[maxn],w[maxn],pre[maxn],dp[maxn];
struct line {
	ll m, b;
	line() { m = 0, b = INFL; }
	line(ll m, ll b) : m(m), b(b) { }
	ll get(ll x) { return m * x + b; }
};

struct LiChao {
	struct node {
		node *l, *r;
		line x;
		node(line x) : x(x) { l = r = 0; }
	};

	node *t = new node(line());

	void upd(line x, node *&v, int l = 0, int r = maxn) {
		if (!v) { v = new node(x); return; }
		int m = (l + r) / 2;
		bool lf = x.get(l) < v->x.get(l);
		bool md = x.get(m) < v->x.get(m);
		if (md) swap(x, v->x);
		if (l == r) return;
		if (lf != md) upd(x, v->l, l, m);
		else upd(x, v->r, m+1, r);
	}

	ll get(int x, node *&v, int l = 0, int r = maxn) {
		if (!v) return INFL;
		int m = (l + r) / 2;
		if (l == r) return v->x.get(x);
		if (x < m) return min(v->x.get(x), get(x, v->l, l, m));
		else return min(v->x.get(x), get(x, v->r, m+1, r));
	}

	void add(line x) { return upd(x, t); }
	ll get(int x) { return get(x, t); }
}cht;
void solve()
{
    cin >> n;
    fo(i, 1, n) cin >> h[i];
    fo(i, 1, n)
    {
        cin >> w[i];
        pre[i] = pre[i - 1] + w[i];
    }
    cht.add({-2 * h[1], h[1] * h[1] - w[1]});
    dp[1] = 0;
    fo(i, 2, n)
    {
        dp[i] = cht.get(h[i]) + pre[i - 1] + h[i] * h[i];
        cht.add({-2 * h[i],h[i] * h[i] - pre[i] + dp[i]});
    }
    cout << dp[n];
}
main()
{
//    freopen("bridgepol.inp","r",stdin);
//    freopen("bridgepol.out","w",stdout);
    ios_base::sync_with_stdio(false);
    cin.tie(NULL);
    solve();
    return 0;
}

Compilation message (stderr)

building.cpp:72:1: warning: ISO C++ forbids declaration of 'main' with no type [-Wreturn-type]
   72 | main()
      | ^~~~

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