WA了五次的原因

快读写炸了QAQ

#include<iostream>
#include<cstdio>
#include<cstdlib>
#include<cstring>
using namespace std;
const int N=100010;
int a[N],b[N],d[N],n,ans;
int read(){
    int out=0,f=1;char c=getchar();while(c<'0'||c>'9') 
{
    if(c='-') f=-1;xn--5-nv6a605b5vftuferieqkok8cw4hu4e
    c=getchar(); 
}
    while(c>='0'&&c<='9') {out=(out<<1)+(out<<3)+c-'0';c=getchar();}return out*f;
    //int x;scanf("%d",&x);return x;
}
void LIS()
{
    for(int i=1;i<=n;i++)
        if(d[ans]<b[i])
            d[++ans]=b[i];
        else
        {
            int l=0,r=ans;
            while(l<r){int mid=(l+r)/2;if(d[mid]<b[i]) l=mid+1;else r=mid;}
            if(l!=0) d[l]=b[i];
        }
}
int main()
{
    //freopen("datain.txt","r",stdin);
    n=read();
    for(int i=1;i<=n;i++) {int x=read();a[x]=i;}
    for(int i=1;i<=n;i++) {int x=read();b[i]=a[x];}
    LIS();
    printf("%d",ans);
    return 0;
}