Submission #276261

#	Time	Username	Problem	Language	Result	Execution time	Memory
276261		anubhavdhar	Building Bridges (CEOI17_building)	C++11	100 / 100	151 ms	11384 KiB

building

#include<bits/stdc++.h>

#define ll long long
#define pb push_back
#define mp make_pair
#define pii pair<int, int>
#define pll pair<ll, ll>
#define ff first 
#define ss second
#define vi vector<int>
#define vl vector<ll>
#define vii vector<pii>
#define vll vector<pll>
#define FOR(i,N) for(i=0;i<(N);++i)
#define FORe(i,N) for(i=1;i<=(N);++i)
#define FORr(i,a,b) for(i=(a);i<(b);++i)
#define FORrev(i,N) for(i=(N);i>=0;--i)
#define F0R(i,N) for(int i=0;i<(N);++i)
#define F0Re(i,N) for(int i=1;i<=(N);++i)
#define F0Rr(i,a,b) for(ll i=(a);i<(b);++i)
#define F0Rrev(i,N) for(int i=(N);i>=0;--i)
#define all(v) (v).begin(),(v).end()
#define dbgLine cerr<<" LINE : "<<__LINE__<<"\n"
#define ldd long double

using namespace std;

const int Alp = 26;
const int __PRECISION = 9;
const int inf = 1e9 + 8;

const ldd PI = acos(-1);
const ldd EPS = 1e-7;

const ll MOD = 1e9 + 7;
const ll MAXN = 1e5 + 5;
const ll ROOTN = 320;
const ll LOGN = 18;
const ll INF = 1e18 + 1022;

int N;
ll dp[MAXN], pre[MAXN], h[MAXN];

struct line
{
	mutable ll m, c, p, isline;
	bool operator < (const line& o) const { return ((o.isline) ? (m < o.m) : (p < o.p));}
};

struct CHT : multiset<line>
{
	ll mode;
	CHT() { mode = 1;}
	inline void set_mode(string s){if(s[1] == 'i' or s[1] == 'I') mode = -1;}
	ll div(ll a, ll b) {return (a/b - ((a^b)<0 && a%b));}
	bool isect(iterator x, iterator y)
	{
		if(y == end()) {x->p = INF; return false;}
		if(x->m == y->m) x->p = (x->c > y->c) ? INF : -INF;
		else x->p = div((y->c - x->c),(x->m - y->m));
		return x->p >= y->p;
	}
	void add(ll sl, ll in)
	{
		auto z = insert({mode*sl, mode*in, 0, 1}), y = z++, x = y;
		while(isect(y, z))	z = erase(z);
		if(x != begin() and isect(--x, y))	isect(x, y = erase(y));
		while((y=x) != begin() and (--x)->p >= y->p)	isect(x, erase(y));
	}
	ll query(ll x)
	{
		assert(!empty());
		auto l = *lower_bound({0, 0, x, 0});
		return mode*(l.m * x + l.c);
	}
}box;

signed main()
{

	/*
	ios_base::sync_with_stdio(false);
	cin.tie(NULL);
	cout.tie(NULL);
	*/

	ll w;
	cin>>N;
	F0R(i, N)
		cin>>h[i];
	F0R(i, N)
		cin>>w, pre[i] = w + ((i == 0) ? 0 : pre[i-1]);

	box.set_mode("min");

	dp[0] = 0;
	box.add( - 2*h[0], h[0]*h[0] + dp[0] - pre[0]);

	F0Re(i, N-1)
	{
		dp[i] = (h[i] * h[i] + pre[i-1]) + box.query(h[i]);
		box.add(- 2*h[i], h[i]*h[i] + dp[i] - pre[i]);
	}
	
	//F0R(i, N)
	//	cout<<"dp["<<i<<"] = "<<dp[i]<<'\n';
	cout<<dp[N-1]<<'\n';

	return 0;
}

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