UCF “Practice” Local Contest — Aug 25, 2018 Boots Exchange 水题

#include <bits/stdc++.h>
using namespace std;

int n;
set <int> a;
map <int,int> cnt;

int main()
{
    cin >> n; int ans = 0;
    for (int i = 1; i <= n; ++i) 
    {
        int x; cin >> x; 
        a.insert(x);
        ++cnt[x];
    }
    for (int i = 1; i <= n; ++i)
    {
        int x; cin >> x;
        if(a.count(x) && cnt[x]) --cnt[x];
        else ans++;
    }
    cout << ans << endl;
    return 0;
}