Submission #161901

#	Time	Username	Problem	Language	Result	Execution time	Memory
161901		amoo_safar	Building Bridges (CEOI17_building)	C++14	100 / 100	167 ms	15996 KiB

building

#include <bits/stdc++.h>
#include <ext/pb_ds/assoc_container.hpp>
 
#define pb push_back
#define F first
#define S second
#define all(x) x.begin(), x.end()
#define debug(x) cerr << #x << " : " << x << '\n'
 
using namespace std;
using namespace __gnu_pbds;
 
typedef long long ll;
typedef long double ld;
typedef string str;
typedef pair<ll, ll> pll;
typedef tree<ll, null_type, less<ll>, rb_tree_tag, tree_order_statistics_node_update> ordered_set;
 
const ll Mod = 998244353;
const ll Inf = LONG_LONG_MAX;
const ll Log = 20;
const ll N = 1ll << Log;
const int Maxn = 1e5 + 10;
const int Maxk = 101;
const int Base = 101;


typedef pair < ll , ll > Line;
struct CHT{
    set < pair < Line , ll > > S;
    set < pair < ll , Line > > I;
    ll INF = 4e18;
    inline void Add(Line X)
    {
    	X.F *= -1;
    	X.S *= -1;
        ll t = -INF;
        auto it = S.lower_bound({X, -INF});
        while ((int)S.size())
        {
            if (it == S.begin())
                {t = -INF; break;}
            it --; ll r = Intersection(it->first, X);
            if (r <= it->second)
                I.erase({it->second, it->first}), it = S.erase(it);
            else
                {t = r; break;}
        }
        it = S.lower_bound({X, -INF});
        while ((int)S.size())
        {
            if (it == S.end())
                break;
            ll r = Intersection(X, it->first);
            Line Y = it->first;
            I.erase({it->second, it->first});
            it = S.erase(it);
            if (r <= t)
            {
                r = -INF;
                if (it != S.begin())
                    it --, r = Intersection(it->first, Y);
                S.insert({Y, r}); I.insert({r, Y}); return ;
            }
            if (it != S.end() && it->second <= r)
                continue;
            S.insert({Y, r}); I.insert({r, Y}); break;
        }
        S.insert({X, t}); I.insert({t, X});
    }
    inline ll GetMin(ll X)
    {
        auto it = I.upper_bound({X, {INF, INF}}); it --;
        return -(X * it->second.first + it->second.second);
    }
    inline ll Intersection(Line X, Line Y)
    {
        if (X.first == Y.first && X.second <= Y.second)
            return (-INF);
        if (X.first == Y.first)
            return (INF);
        return ((X.second - Y.second) / (Y.first - X.first)) + ((X.second - Y.second) % (Y.first - X.first) > 0);
    }
};
CHT cht;

ll h[Maxn], w[Maxn], dp[Maxn], ps[Maxn];

int main(){
	ios::sync_with_stdio(0); cin.tie(0); cout.tie(0);
	ll n;
	cin >> n;
	for(int i = 1; i <= n; i++) cin >> h[i];
	for(int i = 1; i <= n; i++) cin >> w[i];
	for(int i = 1; i <= n; i++) ps[i] = ps[i - 1] + w[i];
	
	dp[1] = 0;
	cht.Add({-2LL * h[1], h[1] * h[1] + dp[1] - ps[1]});
	for(int i = 2; i <= n; i++){
		dp[i] = cht.GetMin(h[i]) + h[i] * h[i] + ps[i - 1];
		cht.Add({-2LL * h[i], h[i] * h[i] + dp[i] - ps[i]});	
	}
	cout << dp[n];
	return 0;
}
/*
6
3 8 7 1 6 6
0 -1 9 1 2 0
*/

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