lis20分，求大佬差错

#include<iostream>
#include<cstdio>
#include<cstring>
#include<algorithm>
#include<cmath>
using namespace std;
const int maxn=100005;
int a[maxn],b[maxn],map[maxn],c[maxn],stk[maxn],up;

 int main(){

int n;

scanf("%d",&n);
for(int 
i=1;i<=n;i++)

   {

    scanf("%d",&a[i]);
   }

   for(int i=1;i<=n;i++)

   {

    scanf("%d",&b[i]);

   map[b[i]]=i;
   }

    for(int i=1;i<=n;i++)

    {
      c[i]=map[a[i]];

    } 

    stk[0]=-100005;
       for(int i=1;i<=n;i++)
      {
        if(c[i]>stk[up])
        {
            stk[++up]=c[i];

        }
        else
        {
            int l=1,r=up,m;
            while(l<=r)
          {
            m=(l+r)/2;
            if(c[i]>stk[m])l=m+1;
            else
            r=m-1;

          }
          stk[m]=c[i];
        }  
      } 
   cout<<up<<endl;
   return 0;

}