1315B - Homecoming

using namespace std;
int main(void)
{
    int t;
    cin >> t;
    while (t--)
    {
        int a, b, p;
        string s;
        cin >> a >> b >> p;
        cin >> s;
        int length = s.size();
        char pchar = s[length - 1];
        int size_travel = 1;
        int ctrav;
        int i;
        int ans = length - 1;
        for (i = length - 2; i >= 0; i--)
        {
            while (i >= 0 and s[i] == pchar)
            {
                ++size_travel;
                --i;
            }
            ctrav = s[i + 1] == 'A' ? a : b;
            if (i < 0)
                break;
            if (i + 1 == length - 1)
                ctrav = 0;
            pchar = s[i];
            if (p - ctrav < 0)
                break;
            p -= ctrav;
            ans = i + 1;
        }
        if (i == -1)
        {
            ctrav = s[i + 1] == 'A' ? a : b;
            if (p - ctrav >= 0)
                ans = i + 1;
        }
        cout << ans + 1 << endl;
    }
    return 0;
}