Polyglot Advent of Code 2016

Advent of Code 2016 is a programming contest, in which a new puzzle comes online every day from 1 until 25 December. These are my solutions to the puzzles. As an additional challenge, I solved each day's puzzle in a different programming language.

Languages

I used only "mainstream" programming languages, not esoteric or toy languages, because this will be hard enough as is. However, I did include some older languages in the list out of historic interest. Plus, a free (as in beer) implementation for Linux has to exist.

Languages I could still have used, roughly in order of decreasing preference (based both on what I know, and what might be suitable for such puzzles):

• Java
• PHP
• BASIC
• Clojure
• Elixir
• CoffeeScript
• Dart
• Nim
• REBOL
• Forth
• F#
• Kotlin
• Octave
• Erlang
• Icon
• Eiffel
• Prolog
• CUDA
• GLSL
• TCL
• Smalltalk
• Julia
• AWK
• J
• APL
• Ada
• Algol
• 6502 assembly

Used:

• C (day 23)
• C++ (day 24)
• C# (day 17)
• COBOL (day 1)
• D (day 11)
• Fortran 90 (day 8)
• Go (day 25)
• Groovy (day 13)
• Haskell (day 16)
• Haxe (day 22)
• JavaScript (day 20)
• Lua (day 18)
• OCaml (day 12)
• OpenCL (day 14)
• Pascal (day 10)
• Pen and paper (and a calculator) (day 15)
• Perl (day 21)
• Python (day 5)
• R (day 6)
• Ruby (day 19)
• Rust (day 9)
• Scala (day 3)
• Scheme (day 2)
• Sh (bash and common shell utilities) (day 4)
• x86 assembly (day 7)

Rules

• Input should be read from stdin if at all possible. Otherwise, read from a file named input.
• The input file must be read and parsed exactly as provided. No modifications are allowed.