EGROUP C++

#include <bits/stdc++.h>
using namespace std;
int n,a[100001],f[100001],b[100001],res=0,resf,resg,maxx=1;
int g[1000005];

void nhap()
{
    cin>>n;
    for(int i=1;i<=n;i++)
        cin>>a[i];
}

int bs_f(int x,int l,int r)
{
    int res=0,m;
    while(l<=r)
    {
        m=(l+r)/2;
        if(a[b[m]]>=x)
        {
            res=m;
            l=m+1;
        }
        else r=m-1;
    }
    return res;
}

int bs_g(int x,int l,int r)
{
    int res=0,m;
    while(l<=r)
    {
        m=(l+r)/2;
        if(a[b[m]]<=x)
        {
            res=m;
            l=m+1;
        }
        else r=m-1;
    }
    return res;
}

void tim_f()
{
    int res,k;
    f[1]=1;res=1;b[1]=1;
    for(int i=2;i<=n;i++)
    {
        k=bs_f(a[i],1,f[res]);
        f[i]=k+1;
        b[f[i]]=i;
        //t[i]=b[k];
        if(f[i]>f[res]) res=i;
    }
    //for(int i=1;i<=res;i++) cout<<b[i]<<" ";
    resf=f[res];
}

void tim_g()
{
    int res,k;
    f[1]=1;res=1;b[1]=1;
    for(int i=2;i<=n;i++)
    {
        k=bs_g(a[i],1,g[res]);
        g[i]=k+1;
        b[g[i]]=i;
        //t[i]=b[k];
        if(g[i]>g[res]) res=i;
    }
    //for(int i=1;i<=res;i++) cout<<b[i]<<" ";
    resg=g[res];
}

void giai()
{
    tim_f();
    tim_g();
    int res=min(n-resf,n-resg);
    cout<<res;
}

void xuat()
{
    res=maxx;
    for (int i=n;i>=1;i--)
    {
        if (res==f[i])
        {
            a[res]=i;
            res--;
        }
        if (res==0) break;
    }
    cout<<maxx<<endl;
    for (int i=1;i<=maxx;i++) cout<<a[i]<<" ";
}

int main()
{
    ios_base::sync_with_stdio(false);
    cin.tie(0);
    cout.tie(0);
    freopen("egroup.inp","r",stdin);
    freopen("egroup.out","w",stdout);
    //xuli();
    //xuat();
    nhap();
    giai();
}