[gjm11]

Dunno if it's helpful for diagnosis, but my 01.txt that yields the expected sha256 sum ...

... is 0x3E1051 bytes long

... starts with <<Congratulations>>, as you already knew it should

... ends with <<IX%7M3+]vW7+zB]{\>>

(It couldn't be line-ending issues, could it? Do you have any 0x0D bytes?)

And, just in case it helps, my original text file (before stripping everything up to 1.#####, and _without_ the spurious 0x0A byte) is 0x3E404D bytes long and ends with << vhuY!niauago>>.

[larryboyko]

Hm. My 01.txt that yields the expected SHA256 sum of a2e617919bc0b981a4f9bb8470ed37d189958e4c5b167e58b417a84c29a66c29

is:

... 0x3e1175 bytes long

... starts with «Congratulations!»

... ends with «ZO?-m[FmGp-+;KM»

[gjm11]

Am I working with an older version of the file or something, perhaps? My copy of the initial file says:

01: 851fa86ed725c26b712ca1218cdec5782259240e403166c5c6c379b22656290b

and that's the sha256sum of my 01.txt .

[gjm11]

(I bet I am working with an older version -- I ran across an error in one of the puzzles, and presumably you've fixed that now.)

[larryboyko]

Ah ha! That's an older version alright.

Latest at https://github.com/larryboyko/dimityjones/blob/main/DimityJo...

(I hope I've fixed the error ...!)