[ludocode]

That might be rather more difficult than you might expect. Advent of Code uses quite a lot of 64-bit numbers. A bit of googling tells me C64 BASIC only supports 16-bit integers and 32-bit floats. I imagine the other BASICs have similar limitations.

I did 2023 Advent of Code with my own compiler and this was the biggest challenge I ran into. I only had 32-bit integers at the time so I had to manually implement 64-bit math and number formatting within the language to be able to do the puzzles. You would probably have to do the same in BASIC.

[timbit42]

Commodore BASIC, derived from Microsoft's 6502 BASIC, actually has 40-bit floats, with a 32-bit mantissa and 8-bit exponent, not that it would help much, if any, with 64-bit maths.

There are Microsoft BASICs that have 64-bit floats, such as built into ROM on the TRS-80 Model I, III and 4 w/Level 2 BASIC, TRS-80 Model 100/102, TI-99/4(a), Apple III, and MSX systems, or on cartridge such as Microsoft BASIC for the Atari 8-bit computers.