求助：样例过不了

#include<iostream>
#include<cmath>
#include<cstdio>
#include<stdlib.h>
#include<algorithm>
#include<cstring>
#include<vector>
#define MAXN 100005
using namespace std;
int n,a[MAXN],b[MAXN],c[MAXN],cnt=1,ans[MAXN],len=0,sta;
int main()
{
    //freopen(".in","r",stdin);
    //freopen(".out","w",stdout);
    scanf("%d",&n);
    for(int i=1;i<=n;i++)
    {
        scanf("%d",&a[i]);
        if(c[a[i]]!=0)
            c[a[i]]=cnt++;
    }
    for(int i=1;i<=n;i++)
    {
        scanf("%d",&b[i]);
        b[i]=c[b[i]];
    }
    for(int i=1;;i++)
    {
        if(b[i]!=0)
        {
            ans[++len]=b[i];
            sta=i+1;
            break;
        } 
    }
    for(int i=sta;i<=n;i++)
    {
        if(b[i]==0)
        continue;
        if(ans[len]<=b[i])
            ans[++len]=b[i];
        else
            ans[upper_bound(ans,ans+MAXN-1,b[i])-ans]=b[i];
    }
    printf("%d",len);
    return 0;
}