WA5! why?

code:

# include <bits/stdc++.h>

using namespace std;

int gcd(int a, int b)
{
    int c;
    if(a < b)
        swap(a, b);
    while(1)
    {
        a = a % b;
        if(a == 0)
            return b;
        c = a;
        a = b;
        b = c;
    }
}

set <int> gtx;
map <int, int> bot;
map <set <int>, int> gg;

int main()
{
    ios_base::sync_with_stdio(0);
    int q, a, s, i;
    char x;
    cin >> q;

    for(i = 1; i <= q; i++)
    {
        cin >> x >> a;
        if(x == '+')
        {
            bot[a]++;
            gtx.insert(a);

            if(gg[gtx])
                cout << gg[gtx] << '\n';
            else if(gtx.size() == 1)
            {
                s = a;
                gg[gtx] = s;
                cout << s << '\n';
            }
            else
            {
                s = gcd(s, a);
                gg[gtx] = s;
                cout << s << '\n';
            }
        }
        else
        {
            bot[a]--;
            if(bot[a] == 0)
                gtx.erase(a);
            if(gtx.size() == 0)
            {
                cout << 1 << '\n';
                continue;
            }
            if(gg[gtx])
                cout << gg[gtx] << '\n';
            else
            {
                set <int> :: iterator j = gtx.begin();
                s = *j;
                for( ; j != gtx.end(); j++)
                    s = gcd(s, *j);
                gg[gtx] = s;
                cout << s << '\n';
            }
        }
    }
    return 0;
}

Edited by author 05.03.2019 16:25