Tired of Practicing Alone? Let's Talk About VP Matchmaking.

When solving problems alone, I often get bored and want to find a VP partner. But currently, VP in CP mostly happens between friends. We're missing a platform to match with strangers at similar skill levels.

I see competitive programming as entertainment – like a cooperative board game. But this multiplayer game often becomes solo practice. Just like a board game player can visit a board game cafe to find strangers to play with, CP need this kind of matching system.

I don't have technical skills to build this, but I think others want this too. If you have ideas, let's discuss in the comments.

You will see something strange in this code

which is : a > b && a == b && !(a > b && a == b) (a, b are double)

#include <bits/stdc++.h>
using namespace std;
typedef long long ll;
typedef unsigned long long ull;
double qpow(double a, ll b)
{
    double res = 1;
    assert(b >= 0);
    for (; b; b >>= 1)
    {
        if (b & 1)
            res = res * a;
        a = a * a;
    }
    return res;
}
double n, m;
double p;
double check(int x)
{
    double p1 = 1 - p;
    p1 = 1 - qpow(p1, x);
    p1 = 1 / p1 * (n * x + m);
    return p1;
}
void solve()
{
     n = 10, m = 27, p = 2855;
//    scanf("%lf%lf%lf", &n, &m, &p);
    p /= 10000;
    int l = 1, r = 10;
    while (l < r)
    {
        int k = (r - l) / 3;
        int mid1 = l + k;
        int mid2 = l + k * 2;
        double a = check(mid1), b = check(mid2);
        if(mid1 == mid2) {
             cout << (a > b) << endl;
             cout << (a == b) << endl;
             cout << (a > b && a == b) << endl;
             cout << (a < b) << endl;
             cout << *((ull*)(&a)) << endl;
             cout << *((ull*)(&b)) << endl;
             cout << a << endl;
             cout << b << endl;
        }
        if (a > b)
        {
          if(mid1 == mid2) cout << (a == b) << endl;
            l = mid1 + 1;
        }
        else
        {
            r = mid2;
        }
    }
}
int main()
{
   solve();
}

Put this code in custom test with C++17

Could someone explain this?

A very strange little bug has appeared, my rating timeline starts from 1970. For now, I haven't found anyone else who has encountered this bug (of course, I haven't really tried hard to find).

If you click on this link soon enough, you should still be able to see this interesting little bug :

https://mirror.codeforces.com/profile/HHY_zZhu