Submission #1108794

#	Time	Username	Problem	Language	Result	Execution time	Memory
1108794		koukirocks	Building Bridges (CEOI17_building)	C++17	100 / 100	69 ms	12764 KiB

building

#include <bits/stdc++.h>
#define speed ios_base::sync_with_stdio(0); cin.tie(0)
#define all(x) (x).begin(),(x).end()
#define F first
#define S second
//#pragma GCC optimize("O3,unroll-loops")
//#pragma GCC target("avx,avx2")
//#pragma GCC target("popcnt")
 
using namespace std;
typedef long long ll;
typedef unsigned long long ull;
typedef double db;
typedef long double ldb;
typedef pair<int,int> pii;
typedef pair<ll,ll> pll;
 
const ll MAX=2e5+10,P=1e9+7;
const ll INF=0x3f3f3f3f,oo=0x3f3f3f3f3f3f3f3f;
const ldb eps=1e-6;
const ldb PI=acos(-1.0);
const int dir[4][2]={{0,1},{0,-1},{1,0},{-1,0}};
template<typename T>
using vvector = vector<vector<T>>;

struct Node {
    int l,r;
    pll ln;
    Node *lft,*rt;
    Node(int l,int r):l(l),r(r),ln({0,oo}),lft(nullptr),rt(nullptr) {};
    void update(pll ln2) {
        if (l==r) {
            if (ln2.F*l+ln2.S>=ln.F*l+ln.S) swap(ln,ln2);
            return;
        }
        if (ln.F<ln2.F) swap(ln,ln2);
        int mid=l+r>>1;
        if (ln2.F*mid+ln2.S<=ln.F*mid+ln.S) {
            if (!lft) lft=new Node(l,mid);
            lft ->update(ln);
            ln = ln2;
        } else {
            if (!rt) rt = new Node(mid+1,r);
            rt->update(ln2);
        }
        // cout<<l<<" "<<r<<" "<<ln.F<<" "<<ln.S<<" l r ln\n";
    }
    ll query(ll x) {
        int mid=l+r>>1;
        ll ans=ln.F*x+ln.S;
        if (x<=mid and lft) ans=min(ans,lft->query(x));
        else if (x>mid and rt) ans=min(ans,rt->query(x));
        return ans;
    }
};

int main() {
    speed;
    int n;
    cin>>n;
    vector<ll> h(n+1);
    vector<ll> pre(n+1);
    for (int i=1;i<=n;i++) {
        cin>>h[i];
    }
    for (int i=1;i<=n;i++) {
        cin>>pre[i];
        pre[i]+=pre[i-1];
    }
    vector<ll> dp(n+1);
    Node *rt = new Node(0,1e6);
    rt->update({-2*h[1],h[1]*h[1]-pre[1]});
    for (int i=2;i<=n;i++) {
        dp[i]=rt->query(h[i])+h[i]*h[i]+pre[i-1];
        rt->update({-2*h[i],h[i]*h[i]-pre[i]+dp[i]});
        // cout<<dp[i]<<" dp\n";
        // cout<<-2*h[i]<<" "<<h[i]*h[i]-pre[i]+dp[i]<<" ln\n";
    }
    cout<<dp[n]<<"\n";
    return 0;
}


/*
6
3 8 7 1 6 6
0 -1 9 1 2 0
*/

Compilation message (stderr)

building.cpp: In member function 'void Node::update(pll)':
building.cpp:37:18: warning: suggest parentheses around '+' inside '>>' [-Wparentheses]
   37 |         int mid=l+r>>1;
      |                 ~^~
building.cpp: In member function 'll Node::query(ll)':
building.cpp:49:18: warning: suggest parentheses around '+' inside '>>' [-Wparentheses]
   49 |         int mid=l+r>>1;
      |                 ~^~

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