以下是他的代码

#include <bits/stdc++.h>
using namespace std;
#define ll long long
string s,t;
queue<char> Q;
ll a = 0;
ll n = 0;
int main(){
	cin >> s >> t;
    for(ll i = 0;i < s.size();i++){
    	Q.push(s[i]);
	}
	while(!Q.empty()){
		if(Q.front() != t[a]){
			Q.pop();
			n++;
		}
		else if(Q.front() == t[a]){
			Q.pop();
			if(a < t.size()) a++; 
		}
	}
	cout << abs(s.size() - n);
	return 0;
}

为了证明我不是无中生有，这是我的代码

#include <bits/stdc++.h>
using namespace std;
#define ll long long
map<char,ll> book;
int main()
{
	string a,b;
	cin>>a>>b;
	for (ll i = 0; i < a.size(); i ++) book[a[i]] ++;
	ll c = 0;
	for (ll i = 0; i < b.size(); i ++)
	{
		if (book.find(b[i]) != book.end() && book[b[i]] != 0)
		{
			c ++;
			book[b[i]] --;
		}
	}
	printf("%lld",c);
	return 0;
}