This is what the announcement at the contest page says
In XOR_ORDER, the checker had an issue due to which some WA solutions have gotten an AC. This has been fixed for Practice. Since most affected participants did not use this ‘loop hole’ intentionally, we believe it is not fair to rejudge the submissions now, and are leaving it as it is. Apologies for the error.
man, just saw a solution where user just iterating 0 to 10 and checking if there is ans and printing it and it got AC
We don’t need 3 conditions to check for the bits.
The highest bit where a and b differ, b should have the bit on. If we are to have an answer, then b should have this bit on.
So we XOR a, b, c all at this bit and also add this bit’s value to X.
We do the same thing for b and c.
We don’t need to do it for a and c, as if a < b and b < c is satisfied, naturally, a < b < c will hold. Lastly, if this relation doesn’t hold, we know that answer doesn’t exist.
Here’s my solution for reference.
I like this problem.