Why has gkSeni been removed from the list of top contributors?

Hello Codeforces community,

I don't know why people have so much craze for contribution that they resort to cheap techniques like creating fake accounts and upvoting themselves. Check

One thing how this could be solved is by increasing the time taken to register the account. CF can add fields like "Organization" and other things mandatory and increase the size of the form. I am not into system design, so not sure if I am speaking wrong.

Second the captcha checking system is not functioning full correct. If captcha needs "1042 revenge", then "0000 revenge" also gets accepted. The captcha fails to match the digits (0 - 9). I tried and successfully generated accounts by wrong captcha.

Finally, I have seen useful comments getting downvotes for no reason. Check. Unnecessary downvotes of figures like -111.
It would be better if some trustable users can be added as "Blog Moderators" who could examine and maintain the decorum. :)

Cheers!

Nowadays, I find that the submission queues go upto 3rd and 4th page. This has become a bit of problem now as I need to wait for really long time, and I just can't concentrate on other problem. I read one two words again switch my tab to see if I got an AC. Please MikeMirzayanov, solve this issue. I really like practising here.

We are given a set V of distinct binary vectors {v₁, v₂, ...v_n} each of size k.
Now you are free to chose a subset of V, S_V = {v_i1, v_i2, v_i3, ..., v_im} such that

• 1 ≤ i₁ < i₂.... < i_m ≤ n.
• No two rows should be same in the kXm matrix M = [v_i1v_i2...v_im]

We need to minimize m (the size of subset S_V). (ie the columns of M)
For eg: a vector v of size 3 can be [0, 0, 1]^T or [1, 0, 1]^T and 6 more are possible.

Given a Treen with n nodes and n - 1 edges, I have to answer Q queries. In every query, I get a list of nodes of size k,
n₁, n₂, ..., n_k. I need to answer the minimum number of paths that are required that cover all of these nodes.