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Create an implementation of the rotational cipher, also sometimes called the Caesar cipher.
Simulate a bank account supporting opening/closing, withdraws, and deposits of money. Watch out for concurrent transactions!
Create a sentence of the form "One for X, one for me."
Implement an evaluator for a very simple subset of Forth
Implement a basic reactive system.
Output the nursery rhyme 'This is the House that Jack Built'.
Tally the results of a small football competition.
Compute the result for a game of Hex / Polygon
Pick the best hand(s) from a list of poker hands.
Make a chain of dominoes.
Parallel Letter Frequency
Count the frequency of letters in texts using parallel computation.
Variable Length Quantity
Implement variable length quantity encoding and decoding.
Creating a zipper for a binary tree.
To try and encourage more sales of different books from a popular 5 book series, a bookshop has decided to offer discounts of multiple-book purchases.
Implement complex numbers.
Rail Fence Cipher
Implement encoding and decoding for the rail fence cipher.
Given the size, return a square matrix of numbers in spiral order.
Create a program to solve a word search puzzle.
Refactor a Markdown parser
Reparent a graph on a selected node
Count the rectangles in an ASCII diagram.
Search a file for lines matching a regular expression pattern. Return the line number and contents of each matching line.
Generate musical scales, given a starting note and a set of intervals.
Implement various kinds of error handling and resource management
Parsing a Smart Game Format string.
Write a Domain Specific Language similar to the Graphviz dot language
Count the scored points on a Go board.
Implement the logic of the hangman game using functional reactive programming.
Refactor a ledger printer.
Use lenses to update nested records (specific to languages with immutable data).
Refactor a tree building algorithm.
Report network IO statistics
Check if a given string is a valid ISBN-10 number.