HJ10 字符个数统计 | 杂乱无章的初级程序员的题解

#include <iostream>
#include <unordered_set>

using namespace std;

int main()
{
    unordered_set<char> s;
    char c;
    cin >> noskipws;
    while (cin >> c) {
        if (c == '\n') {
            break;
        }
        s.insert(c);
    }
    cout << s.size() << endl;
    return 0;
}