1720: 集合

#include <iostream>
#include <cstdio>
#include <algorithm>
#include <cstring>
using namespace std;
#define maxn 100005
#define maxm 2000000
int na,nb,now[maxm],prep[maxn],val[maxn];
void read(int &x){
    x=0; int f=1; char ch;
    for (ch=getchar();!isdigit(ch);ch=getchar()) if (ch==‘-‘) f=-1;
    for (;isdigit(ch);ch=getchar()) x=x*10+ch-‘0‘; x*=f;
}
void Ha(int x){
    int pos=val[x]%maxm+1;
    prep[x]=now[pos],now[pos]=x;
}
bool search(int x){
    int pos=x%maxm+1; bool bo=0;
    for (int i=now[pos];i;i=prep[i]){
        if (val[i]==x){
            bo=1; break;
        }
    }
    return bo;
}
int main(){
    memset(now,0,sizeof(now));
    read(na);
    for (int i=1;i<=na;i++) read(val[i]),Ha(i);
    int ans=0;
    read(nb); int x;
    for (int i=1;i<=nb;i++){
        read(x);
        if (!search(x)) ans++;
    } printf("%d\n",ans);
    return 0;
}