Python Coding Challenges

strings character-comparison distance

Hamming Distance

Implement a function that computes the Hamming distance between two strings of equal length.

Hex encode decode

Write hex_encode and hex_decode to convert between hex strings and integer byte values.

hex encoding strings

strings cipher transformation

ROT13 Transform

Implement ROT13, a letter substitution cipher that rotates the alphabet by 13 positions.

Caesar Cipher Decrypt

Implement a function that decrypts a Caesar cipher by shifting letters back by a given number.

strings ascii cipher

strings deduplication order-preserving

Remove Duplicate Letters

Implement a function that removes duplicate characters from a string while preserving the order of their first occurrence.

url-parsing strings parsing

Parse URL components

Write parse_url that splits a URL into its standard components with defaults for missing parts.

Parse HTTP Status Line

Write a function that parses a well-formed HTTP status line into its three components.

strings parsing http

+8 pts 15m

Parse markdown headers

Write a function that parses markdown headers and returns their levels and texts.

markdown parsing strings

Parse bullet list

Parse a markdown-style bullet list and return the list of item texts, stripping bullet markers and trimming surrounding whitespace.

parsing strings markdown

Decode base64 string

Write a function that decodes a base64 string to its original UTF-8 text without using the base64 module.

base64 decode strings

Parse Version SemVer

Write a function that parses a semantic version string into its numeric components.

strings parsing semver

strings parsing comparison

Compare Version Strings

Given two version strings, compare them numerically by splitting on dots and ignoring leading zeros.

Parse path segments

Implement a function that parses a path string into clean segments, ignoring slashes, empty parts, and dot segments.

strings parsing split

Parse coordinate pairs

Parse a string of coordinate pairs into a list of coordinate lists.

parsing strings split

Parse range notation

Parse a comma-separated list of ranges and individual numbers, expanding each range into its full sequence.

strings parsing ranges

Parse Boolean Strings

Implement a function that parses a boolean string into a Python bool, handling True/False/Yes/No/1/0 case-insensitively.

strings boolean parsing

strings formatting cleaning

User Friendly Message

Given a raw user input, format it into a single clean sentence with proper sentence case and trimming.

Crawler Log Folder

Given a list of folder navigation operations, compute the minimum steps required to return to the main folder.

strings stack simulation

Caesar Cipher Decrypt

Write a function that decrypts a Caesar cipher by shifting letters backward by a given key.

strings cipher ascii

First non-repeating character

Find the index of the first character that appears only once.

dict strings counter

+12 pts 12m

dictionaries strings grouping

Group names by first letter

Given a list of names, return a dictionary mapping each first letter to all names starting with that letter in original order.

sorting dictionaries ordering

Keys Sorted by Value Descending

Given a dictionary mapping strings to integers, return a list of keys sorted by value descending, and when values tie, alphabetically ascending.

Anagram Dictionary Groups Lite

Group a list of words into anagrams using a dictionary keyed by sorted characters.

dicts strings anagrams

Anagram Groups by Size

Group a list of words into anagram groups and return them sorted by group size and lexicographically.

dicts sets sorting