# Perl 5

### Add new Perl 5 exercises

One of the easiest ways to add new exercises to the Perl 5 track is to translate them from other language tracks on Exercism. This page lists all of the problem specifications in the common pool of exercises which have not yet been implemented in Perl 5.

The icon links to the language-independent description of the problem.

The icon links to the canonical test data.

We also link to all the implementations of each exercise in other languages, which you can use for inspiration.

Once you've picked an exercise, follow the instructions in this guide and submit your pull request to the Perl 5 track repository on GitHub.

### Pangram

Determine if a sentence is a pangram.

### Acronym

Convert a long phrase to its acronym

### Isogram

Determine if a word or phrase is an isogram.

### Collatz Conjecture

Calculate the number of steps to reach 1 using the Collatz conjecture

### Bracket Push

Make sure the brackets and braces all match.

### Nth Prime

Given a number n, determine what the nth prime is.

### Perfect Numbers

Determine if a number is perfect, abundant, or deficient based on Nicomachus' (60 - 120 CE) classification scheme for natural numbers.

### Two Fer

Create a sentence of the form "One for X, one for me."

### Run Length Encoding

Implement run-length encoding and decoding.

### Diamond

Given a letter, print a diamond starting with 'A' with the supplied letter at the widest point.

### Flatten Array

Take a nested list and return a single list with all values except nil/null

### Rotational Cipher

Create an implementation of the rotational cipher, also sometimes called the Caesar cipher.

### Bowling

Score a bowling game

### Isbn Verifier

Check if a given string is a valid ISBN-10 number.

### Change

Correctly determine change to be given using the least number of coins

### Transpose

Take input text and output it transposed.

### Armstrong Numbers

Determine if a number is an Armstrong number

### Circular Buffer

A data structure that uses a single, fixed-size buffer as if it were connected end-to-end.

### Protein Translation

Translate RNA sequences into proteins.

### Bank Account

Simulate a bank account supporting opening/closing, withdraws, and deposits of money. Watch out for concurrent transactions!

### Complex Numbers

Implement complex numbers.

Reverse a string

### React

Implement a basic reactive system.

### Spiral Matrix

Given the size, return a square matrix of numbers in spiral order.

### Alphametics

Write a function to solve alphametics puzzles.

### Connect

Compute the result for a game of Hex / Polygon

### Dominoes

Make a chain of dominoes.

### Forth

Implement an evaluator for a very simple subset of Forth

### Poker

Pick the best hand(s) from a list of poker hands.

### Rail Fence Cipher

Implement encoding and decoding for the rail fence cipher.

### Rectangles

Count the rectangles in an ASCII diagram.

### Tournament

Tally the results of a small football competition.

### Variable Length Quantity

Implement variable length quantity encoding and decoding.

### Zipper

Creating a zipper for a binary tree.

### Book Store

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.

### Diffie Hellman

Diffie-Hellman key exchange.

### Parallel Letter Frequency

Count the frequency of letters in texts using parallel computation.

### Two Bucket

Given two buckets of different size, demonstrate how to measure an exact number of liters.

### Markdown

Refactor a Markdown parser

### Grep

Search a file for lines matching a regular expression pattern. Return the line number and contents of each matching line.

### Pov

Reparent a graph on a selected node

### Scale Generator

Generate musical scales, given a starting note and a set of intervals.

### Word Search

Create a program to solve a word search puzzle.

### Error Handling

Implement various kinds of error handling and resource management

### Rational Numbers

Implement rational numbers.

### Zebra Puzzle

Solve the zebra puzzle.

### Go Counting

Count the scored points on a Go board.

### Sgf Parsing

Parsing a Smart Game Format string.

### Dot Dsl

Write a Domain Specific Language similar to the Graphviz dot language

### Tree Building

Refactor a tree building algorithm.

### Yacht

Score a single throw of dice in the game Yacht

### Hangman

Implement the logic of the hangman game using functional reactive programming.

### Ledger

Refactor a ledger printer.

### Lens Person

Use lenses to update nested records (specific to languages with immutable data).

### Paasio

Report network IO statistics