Submission #1265068

#	Time	Username	Problem	Language	Result	Execution time	Memory
1265068		escobrand	Building Bridges (CEOI17_building)	C++20	100 / 100	68 ms	65352 KiB

building

// Li-chao Tree
/* documents
  tài liệu của lanciu
  
*/
#include <bits/stdc++.h>

using namespace std;
#define all(v) v.begin(),v.end()
#define pb push_back
#define ll long long
#define ld long double
#define fi first
#define se second
#define mk make_pair
typedef pair<int,int> pii;

const int maxn = 1e5 + 10;
ll a[maxn],pre[maxn],dp[maxn];

// Code Li-chao Tree
struct Line 
{
  ll a,b;
  Line():a(0),b(0){}
  Line(ll A,ll B) : a(A),b(B){}
  
  ll cal(ll x) const {return a * x + b;}
};

struct Lichao 
{
  vector<Line> t;
  
  Lichao(){} 
  Lichao(int sz) : t(sz * 4,Line(0,LLONG_MAX)){}
  
  void up(int i,int tl,int tr,Line f)
  {
    int mid = (tl + tr)/2;
    if( f.cal(mid) < t[i].cal(mid) ) swap(t[i],f);
    
    if(tl == tr) return;
    
    if(f.a > t[i].a) up(i * 2,tl,mid,f);
    if(f.a < t[i].a) up(i * 2 + 1,mid+1,tr,f);
  }
  
  ll cal(int i,int tl,int tr,int pos)
  {
    if(tl > tr || tl > pos || tr < pos)return LLONG_MAX;
    ll ans = t[i].cal(pos);
    if(tl == tr)return ans;
    int mid = (tl + tr)/2;
    ans = min(ans, cal(i*2,tl,mid,pos) );
    ans = min(ans, cal(i * 2 + 1,mid+1,tr,pos) );
    return ans;
  }
};
// End Code Li-chao Tree

int main()
{
    ios_base::sync_with_stdio(false);
    cin.tie(0);
    
    // https://oj.uz/problem/view/CEOI17_building?locale=en
    
    int n;
    cin>>n;
    for(int i = 1;i<=n;i++)cin>>a[i];
    for(int i = 1;i<=n;i++)
    {
        cin>>pre[i];
        pre[i] += pre[i-1]; 
    }
    
    Lichao tree(1000000 + 10); 
    
    for(int i = 1;i<=n;i++)
    {
        if(i == 1)
        {
            dp[i] = 0; 
        }
        else
        {
            dp[i] = tree.cal(1,0,1000000,a[i]) + a[i] * a[i] + pre[i-1];
        }
          // Add new line for future DP queries
        tree.up(1,0,1000000,Line( a[i] * -2, a[i] * a[i] +dp[i] - pre[i] ));
    }
    
    cout<<dp[n]; 
    
    return 0;
}

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