参考答案：

#include<iostream>
#include<cstring>

using namespace std;

const int N = 200003, null = 0x3f3f3f3f;
int h[N];

int find(int x)
{
    int t = ((x % N) + N) % N;

    while (h[t] != null && h[t] != x)
    {
        ++t;
        if (t == N) t = 0;
    }

    return t;
}
int main()
{
    memset(h, 0x3f, sizeof(h));
    int n;

    cin >> n;
    while (n--)
    {
        int x;
        char op[2];
        scanf("%s%d", op, &x);
        if (*op == 'I') h[find(x)] = x;
        else
        {
            if (h[find(x)] == x) cout << "Yes" << endl;
            else cout << "No" << endl;
        }
    }

    return 0;
}