Ositus

#include <iostream>

using namespace std;

unsigned int partition(string part, string s)
{
    if (s.size() == 1)
        return 1;
    else
    {
        return partition("", s.substr(1)) + ((part + s[0]).find(s[1]) == string::npos ? partition(part + s[0], s.substr(1)) : 0);
    }
}

int main()
{
    string s;
    cin >> s;
    cout << partition("", s);
}

Test 1

Group: 1, 2, 3

Verdict: ACCEPTED

Test 2

Group: 1, 2, 3

Verdict: ACCEPTED

Test 3

Group: 1, 2, 3

Verdict: ACCEPTED

Test 4

Group: 1, 2, 3

Verdict: ACCEPTED

Test 5

Group: 2, 3

Verdict: TIME LIMIT EXCEEDED

Test 6

Group: 3

Verdict: TIME LIMIT EXCEEDED

Test 7

Group: 3

Verdict: RUNTIME ERROR