参考代码

#include<bits/stdc++.h>

using namespace std;
typedef long long ll;
typedef pair<int, int> PII;

const int N = 100010;

int n, m;
string s;
set<string> rs;

string tolower(string s)
{
    int n = s.size();
    for (int i = 0; i < n; i++) {
        if (s[i] < 'a') s[i] = char(s[i] + 'a' - 'A');
    }

    return s;
}

void solve()
{
    getline(cin, s);

    cin >> n;
    for (int i = 0; i < n; i++) {
        string t;
        cin >> t;
        rs.insert(t);
    }

    int cnt = 0;
    n = s.size();
    for (int i = 0; i < n;) {
        if (s[i] == ' ') i++;
        else if (s[i] == ',' or s[i] == '.' or s[i] == '!' or s[i] == '?') i++;
        else if (s[i] == '\r' or s[i] == '\n') i++;
        else {
            string t = "";
            while (i < n and s[i] != ' ' and s[i] != ',' and s[i] != '.' and s[i] != '!' and s[i] != '?') t += s[i++];

            t = tolower(t);

            if (rs.find(t) == rs.end()) {
                cnt++;
                rs.insert(t);
            }
        }
    }

    cout << cnt << endl;
}

int main()
{
    int t = 1;
    //cin >> t;
    while (t--)
        solve();

    return 0;
}