Submission #1282213

#	Time	Username	Problem	Language	Result	Execution time	Memory
1282213		quan606303	Building Bridges (CEOI17_building)	C++20	100 / 100	329 ms	10556 KiB

building

/*
 * @Author: RMQuan 
 * @Date: 2025-10-22 22:10:41 
 * @Last Modified by: RMQuan
 * @Last Modified time: 2025-10-22 23:19:43
 */
/*idea : 



*/
#include <bits/stdc++.h>
bool M1;
#define int long long
#define ll long long
#define INTMAX INT_MAX
#define INTMIN INT_MIN
#define LONGMAX LLONG_MAX
#define LONGMIN LLONG_MIN
#define fi first
#define se second
#define memfull(a,b) memset(a,b,sizeof(a));
#define endl '\n'
#define TASK "TEST"
#define file() if (fopen(TASK".inp","r")){freopen(TASK".inp","r",stdin); freopen(TASK".out","w",stdout);}
using namespace std;
const int MOD=1e9+7;
const int maxn=1e5+7;
const int inf=1e18;
int h[maxn],w[maxn],pre[maxn],n,dp[maxn];
struct point
{
    int A,B;
    point()
    {
        A=0;
        B=inf;
    }
    int cal(int x)
    {
        return A*x+B;
    }
    point(int _A,int _B):A(_A),B(_B){}
};
struct LCT_node
{
    LCT_node *L,*R;
    point ans;
    LCT_node()
    {
        L=NULL;
        R=NULL;
        ans=point();
    }
};
struct LCT
{
    LCT_node *root;
    LCT(int cnt)
    {
        root=new LCT_node();
    }
     void upd(LCT_node *p,int l,int r,point val)
    {
        if (val.B>=inf)return ;
        int mid=(l+r)/2;
        if (p->ans.cal(mid)>val.cal(mid))swap(p->ans,val);
        if (l!=r)
        {
            if (val.A>p->ans.A)
            {
                if (p->L==NULL)p->L=new LCT_node();
                upd(p->L,l,mid-1,val);
            }
            else{
                if (p->R==NULL)p->R=new LCT_node();
                upd(p->R,mid+1,r,val);
            }
        }
    }
    int get(LCT_node *p,int l,int r,int pos)
    {
        int cnt=p->ans.cal(pos);
        int mid=(l+r)/2;
        if (pos>mid&&p->R!=NULL)cnt=min(cnt,get(p->R,mid+1,r,pos));
        else if (pos<mid&&p->L!=NULL)cnt=min(cnt,get(p->L,l,mid-1,pos));
        return cnt;
    }
    void update(point val)
    {
        upd(root,0,1e9,val);
    }
    int query(int pos)
    {
        return get(root,0,1e9,pos);
    }
};
int32_t main()
{
    ios_base::sync_with_stdio(0);
    cin.tie(0);
    cout.tie(0);
    file();
    cin>>n;
    for (int i=1;i<=n;i++)cin>>h[i];
    for (int i=1;i<=n;i++)
    {
        cin>>w[i];  
        pre[i]=pre[i-1]+w[i];
    }
    LCT lct(0);
    lct.update(point(-2*h[1],dp[1]+h[1]*h[1]-pre[1]));
    for (int i=2;i<=n;i++)
    {
        dp[i]=lct.query(h[i])+(h[i]*h[i]+pre[i-1]);
       // cerr<<dp[i]<<endl;
        lct.update(point(-2*h[i],dp[i]+h[i]*h[i]-pre[i]));
    }
    cout<<dp[n];
    bool M2;
    cerr<<"-------------------------------------------------"<<endl;
    cerr<<"Time : "<<clock()<<" ms"<<endl;
    cerr<<"Memory : "<<abs(&M2-&M1)/1024/1024<<" MB"<<endl;
    cerr<<"-------------------------------------------------"<<endl;
    return 0;
}

Compilation message (stderr)

building.cpp: In function 'int32_t main()':
building.cpp:25:50: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)' declared with attribute 'warn_unused_result' [-Wunused-result]
   25 | #define file() if (fopen(TASK".inp","r")){freopen(TASK".inp","r",stdin); freopen(TASK".out","w",stdout);}
      |                                           ~~~~~~~^~~~~~~~~~~~~~~~~~~~~~
building.cpp:103:5: note: in expansion of macro 'file'
  103 |     file();
      |     ^~~~
building.cpp:25:81: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)' declared with attribute 'warn_unused_result' [-Wunused-result]
   25 | #define file() if (fopen(TASK".inp","r")){freopen(TASK".inp","r",stdin); freopen(TASK".out","w",stdout);}
      |                                                                          ~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~
building.cpp:103:5: note: in expansion of macro 'file'
  103 |     file();
      |     ^~~~

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