Day 3 Silver.

Switched to C#, and wrote it in vim.  I see that it totally messed up the indentation
with a mix of spaces and tabs, looked normal in vim though.

The code itself ain't too bad.  Bit operations are about the same in C# versus Java versus C.

Day 2 Gold

Day 2 Silver.

Dunno why I'm doing this year's puzzle in Java.  Kotlin in 2020 was kinda nice, though I didn't wind up writing any Kotlin in 2021.  I've been writing mostly C# lately and that's also nice.

But this works.

Day 1 Silver and Gold.  From December 1 but not committed till now.