- Introduction
- Programming tasks
- 1
- 2
- 4
- 9
- A
- A* search algorithm
- A B
- Abbreviations automatic
- Abbreviations easy
- Abbreviations simple
- ABC problem
- ABC words
- Abelian sandpile model
- Abstract type
- Abundant deficient and perfect number classifications
- Abundant odd numbers
- Accumulator factory
- Achilles numbers
- Ackermann function
- Active Directory
- Active object
- Add a variable to a class instance at runtime
- Addition-chain exponentiation
- Addition chains
- Additive primes
- Address of a variable
- ADFGVX cipher
- Air mass
- AKS test for primes
- Algebraic data types
- Align columns
- Aliquot sequence classifications
- Almkvist-Giullera formula for pi
- Almost prime
- Alternade words
- Amb
- Amicable pairs
- Anadromes
- Anagram generator
- Anagrams
- Anaprimes
- Angle difference between two bearings
- Angles geometric normalization and conversion
- Animate a pendulum
- Animation
- Anonymous recursion
- Anti-primes
- Apéry's constant
- Append a record to the end of a text file
- Append numbers at same position in strings
- Apply a callback to an array
- Apply a digital filter direct form II transposed
- Approximate equality
- Arbitrary-precision integers included
- Archimedean spiral
- Arena storage pool
- Arithmetic
- Arithmetic-geometric mean
- Arithmetic coding
- Arithmetic derivative
- Arithmetic evaluation
- Arithmetic numbers
- Array concatenation
- Array length
- Arrays
- Ascending primes
- ASCII art diagram converter
- ASCII control characters
- Aspect oriented programming
- Assertions
- Assertions in design by contract
- Associative array
- Atomic updates
- Attractive numbers
- Audio alarm
- Audio frequency generator
- Autogram checker
- Average loop length
- Averages
- AVL tree
- B
- Bézier curves
- B-spline
- Babbage problem
- Babylonian spiral
- Bacon cipher
- Balanced brackets
- Balanced ternary
- Banker's algorithm
- Barnsley fern
- Base58Check encoding
- Base64 decode data
- Base64 encode data
- Base 16 numbers needing a to f
- Bell numbers
- Benford's law
- Bernoulli numbers
- Bernstein basis polynomials
- Best shuffle
- Bifid cipher
- Bilinear interpolation
- Bin given limits
- Binary coded decimal
- Binary digits
- Binary search
- Binary strings
- Binomial transform
- Bioinformatics
- Biorhythms
- Birthday problem
- Bitcoin
- Bitmap
- Bitwise IO
- Bitwise operations
- Blum integer
- Boolean values
- Boustrophedon transform
- Box the compass
- Boyer-Moore string search
- Brace expansion
- Brace expansion using ranges
- Brazilian numbers
- Break OO privacy
- Brilliant numbers
- Brownian tree
- Bulls and cows
- Burrows Wheeler transform
- C
- Caesar cipher
- Calculating the value of e
- Calendar
- Calendar - for REAL programmers
- Calkin-Wilf sequence
- Call a foreign-language function
- Call a function
- Call a function in a shared library
- Call an object method
- Calmo numbers
- CalmoSoft primes
- Camel case and snake case
- Canny edge detector
- Canonicalize CIDR
- Cantor set
- Card shuffles
- Carmichael 3 strong pseudoprimes
- Carmichael lambda function
- Cartesian product of two or more lists
- Case-sensitivity of identifiers
- Casting out nines
- Catalan numbers
- Catamorphism
- Centre and radius of a circle passing through 3 points in a plane
- Centroid of a set of N-dimensional points
- Change e letters to i in words
- Changeable words
- Chaocipher
- Chaos game
- Character codes
- Chat server
- Chebyshev coefficients
- Check if a polygon overlaps with a rectangle
- Check if two polygons overlap
- Check input device is a terminal
- Check Machin-like formulas
- Check output device is a terminal
- Check that file exists
- Checkpoint synchronization
- Checksumcolor
- Chemical calculator
- Chernick's Carmichael numbers
- Cheryl's birthday
- Chinese remainder theorem
- Chinese zodiac
- Cholesky decomposition
- Chowla numbers
- Church numerals
- Cipolla's algorithm
- Circles of given radius through two points
- Circular primes
- Cistercian numerals
- Classes
- Closest-pair problem
- Closures
- Code Golf Code Golf
- Code segment unload
- Collect and sort square numbers in ascending order from three lists
- Collections
- Color of a screen pixel
- Color quantization
- Color wheel
- Colorful numbers
- Colour bars
- Colour pinstripe
- Combinations
- Combinations and permutations
- Combinations with repetitions
- Comma quibbling
- Command-line arguments
- Commatizing numbers
- Comments
- Common list elements
- Common sorted list
- Compare a list of strings
- Compare length of two strings
- Compare sorting algorithms' performance
- Compile-time calculation
- Compiler
- Composite numbers k with no single digit factors whose factors are all substrings of k
- Compound data type
- Concatenate two primes is also prime
- Concurrent computing
- Conditional structures
- Conjugate a Latin verb
- Conjugate transpose
- Consecutive primes with ascending or descending differences
- Consistent overhead byte stuffing
- Constrained genericity
- Constrained random points on a circle
- Continued fraction
- Continued fraction convergents
- Convert decimal number to rational
- Convert seconds to compound duration
- Convex hull
- Conway's Game of Life
- Coprime triplets
- Coprimes
- Copy a string
- Copy stdin to stdout
- CORDIC
- Count how many vowels and consonants occur in a string
- Count in factors
- Count in octal
- Count occurrences of a substring
- Count the coins
- Countdown
- Cousin primes
- Cramer's rule
- CRC-32
- Create a file
- Create a file on magnetic tape
- Create a two-dimensional array at runtime
- Create an HTML table
- Create an object
- Create an object at a given address
- Create your own text control codes
- CSV data manipulation
- CSV to HTML translation
- Cuban primes
- Cubic special primes
- Cullen and Woodall numbers
- Cumulative standard deviation
- Currency
- Currying
- Curve that touches three points
- Curzon numbers
- CUSIP
- Cut a rectangle
- Cycle detection
- Cycles of a permutation
- Cyclops numbers
- Cyclotomic polynomial
- D
- Damm algorithm
- Data Encryption Standard
- Date format
- Date manipulation
- Dating agency
- Day of the week
- Day of the week of Christmas and New Year
- Days between dates
- De Bruijn sequences
- De Polignac numbers
- Deal cards for FreeCell
- Death Star
- Deceptive numbers
- Decimal floating point number to binary
- Decision tables
- Deconvolution
- Decorate-sort-undecorate idiom
- Deepcopy
- Define a primitive data type
- Delegates
- Delete a file
- Deming's funnel
- Department numbers
- Descending primes
- Detect division by zero
- Determinant and permanent
- Determine if a string has all the same characters
- Determine if a string has all unique characters
- Determine if a string is collapsible
- Determine if a string is numeric
- Determine if a string is squeezable
- Determine if only one instance is running
- Determine if two triangles overlap
- Determine sentence type
- Dice game probabilities
- Digit fifth powers
- Digital root
- Dijkstra's algorithm
- Dinesman's multiple-dwelling problem
- Dining philosophers
- Disarium numbers
- Discordian date
- Discrete Fourier transform
- Display a linear combination
- Display an outline as a nested table
- Distance and Bearing
- Distinct palindromes within decimal numbers
- Distinct power numbers
- Distributed programming
- Distribution of 0 digits in factorial series
- Diversity prediction theorem
- Divide a rectangle into a number of unequal triangles
- DNS query
- Documentation
- Doomsday rule
- Dot product
- Double Twin Primes
- Doubly-linked list
- Dragon curve
- Draw a clock
- Draw a cuboid
- Draw a pixel
- Draw a rotating cube
- Draw a sphere
- Draw pixel 2
- Duffinian numbers
- Dutch national flag problem
- Dynamic variable names
- E
- Earliest difference between prime gaps
- Eban numbers
- Echo server
- Eertree
- Egyptian division
- Eisenstein primes
- EKG sequence convergence
- Element-wise operations
- Elementary cellular automaton
- Elliptic curve arithmetic
- Elliptic Curve Digital Signature Algorithm
- Emirp primes
- Empty directory
- Empty program
- Empty string
- Enforced immutability
- Engel expansion
- English cardinal anagrams
- Entropy
- Enumerations
- Environment variables
- Equal prime and composite sums
- Equilibrium index
- Erdös-Selfridge categorization of primes
- Erdős-Nicolas numbers
- Erdős-primes
- Erdős Woods numbers
- Esthetic numbers
- Ethiopian multiplication
- Euclid-Mullin sequence
- Euclidean rhythm
- Euler's constant 0 5772
- Euler's identity
- Euler's sum of powers conjecture
- Euler method
- Evaluate binomial coefficients
- Even numbers which cannot be expressed as the sum of two twin primes
- Even or odd
- Events
- Evolutionary algorithm
- Exactly three adjacent 3 in lists
- Exceptions
- Executable library
- Execute a Markov algorithm
- Execute a system command
- Execute Brain****
- Execute Computer
- Execute CopyPasta Language
- Execute HQ9
- Execute SNUSP
- Exponential digital sums
- Exponentiation operator
- Exponentiation order
- Exponentiation with infix operators in or operating on the base
- Extend your language
- Extensible prime generator
- External sort
- Extra primes
- Extract file extension
- Extreme floating point values
- Extreme primes
- F
- Faces from a mesh
- Factor-perfect numbers
- Factorial
- Factorial base numbers indexing permutations of a collection
- Factorial primes
- Factorions
- Factorize string into Lyndon words
- Factors of a Mersenne number
- Factors of an integer
- Fairshare between two and more
- Farey sequence
- Fast Fourier transform
- FASTA format
- Faulhaber's formula
- Faulhaber's triangle
- Feigenbaum constant calculation
- Fermat numbers
- Fermat pseudoprimes
- Fibonacci heap
- Fibonacci matrix-exponentiation
- Fibonacci n-step number sequences
- Fibonacci sequence
- Fibonacci word
- File extension is in extensions list
- File input
- File modification time
- File size
- File size distribution
- Filter
- Find adjacent primes which differ by a square integer
- Find Chess960 starting position identifier
- Find common directory path
- Find duplicate files
- Find first and last set bit of a long integer
- Find first missing positive
- Find if a point is within a triangle
- Find largest left truncatable prime in a given base
- Find limit of recursion
- Find minimum number of coins that make a given value
- Find palindromic numbers in both binary and ternary bases
- Find prime n such that reversed n is also prime
- Find prime numbers of the form nnn 2
- Find square difference
- Find squares n where n 1 is prime
- Find the intersection of a line with a plane
- Find the intersection of two lines
- Find the last Sunday of each month
- Find the missing permutation
- Find URI in text
- Find words which contain the most consonants
- Find words which contains all the vowels
- Find words which contains more than 3 e vowels
- Find words whose first and last three letters are equal
- Find words with alternating vowels and consonants
- Finite state machine
- First-class functions
- First 9 prime Fibonacci number
- First class environments
- First perfect square in base n with n unique digits
- First power of 2 that has leading decimal digits of 12
- Five weekends
- Fivenum
- Fixed length records
- FizzBuzz
- Flatten a list
- Flipping bits game
- Flow-control structures
- Floyd's triangle
- Floyd-Warshall algorithm
- Forbidden numbers
- Forest fire
- Fork
- Formal power series
- Formatted numeric output
- Fortunate numbers
- Forward difference
- Four bit adder
- Four is magic
- Four is the number of letters in the
- Four sides of square
- Fractal tree
- Fraction reduction
- Fractran
- French Republican calendar
- Frobenius numbers
- FTP
- Function composition
- Function definition
- Function frequency
- Function prototype
- Functional coverage tree
- Fusc sequence
- G
- Galton box animation
- Gamma function
- Gapful numbers
- Gauss-Jordan matrix inversion
- Gaussian elimination
- Gaussian primes
- General FizzBuzz
- Generalised floating point addition
- Generate Chess960 starting position
- Generate lower case ASCII alphabet
- Generate random chess position
- Generate random numbers without repeating a value
- Generator
- Generic swap
- Geohash
- Geometric algebra
- Get system command output
- Getting the number of decimal places
- Giuga numbers
- Globally replace text in several files
- Go Fish
- Goldbach's comet
- Golden ratio
- Goodstein Sequence
- Gotchas
- Gradient descent
- Graph colouring
- Gray code
- Grayscale image
- Greatest common divisor
- Greatest element of a list
- Greatest prime dividing the n-th cubefree number
- Greatest subsequential sum
- Greed
- Greedy algorithm for Egyptian fractions
- Greyscale bars
- GSTrans string conversion
- Guess the number
- GUI
- GUI component interaction
- GUI enabling
- H
- Hailstone sequence
- Halt and catch fire
- Hamming numbers
- Handle a signal
- Happy numbers
- Harmonic series
- Harshad or Niven series
- Hash from two arrays
- Hash join
- Hashtron inference
- Haversine formula
- Hello world
- Here document
- Heronian triangles
- Hex dump
- Hex words
- Hickerson series of almost integers
- Higher-order functions
- Hilbert curve
- History variables
- Hofstadter-Conway 10 000 sequence
- Hofstadter Figure-Figure sequences
- Hofstadter Q sequence
- Holidays related to Easter
- Home primes
- Honaker primes
- Horizontal sundial calculations
- Horner's rule for polynomial evaluation
- Horse racing
- Host introspection
- Hostname
- Hough transform
- Hourglass puzzle
- HTTP
- HTTPS
- Huffman coding
- Humble numbers
- Hunt the Wumpus
- I
- I'm a software engineer get me out of here
- I before E except after C
- IBAN
- Iccanobif primes
- Identity matrix
- Idiomatically determine all the characters that can be used for symbols
- Idiomatically determine all the lowercase and uppercase letters
- Idoneal numbers
- Image convolution
- Image noise
- Imaginary base numbers
- Implicit type conversion
- Include a file
- Inconsummate numbers in base 10
- Increasing gaps between consecutive Niven numbers
- Increment a numerical string
- Index finite lists of positive integers
- Infinity
- Inheritance
- Inner classes
- Input
- Input loop
- Integer comparison
- Integer long division
- Integer overflow
- Integer roots
- Integer sequence
- Interactive help
- Interactive programming repl
- Intersecting number wheels
- Introspection
- Inventory sequence
- Inverted index
- Inverted syntax
- IPC via named pipe
- ISBN13 check digit
- Isograms and heterograms
- Isqrt integer square root of X
- Iterated digits squaring
- Iterators
- J
- K
- K-d tree
- K-means clustering
- Kahan summation
- Kaprekar numbers
- Kernighans large earthquake problem
- Keyboard input
- Keyboard macros
- Klarner-Rado sequence
- Knapsack problem
- Knight's tour
- Knuth's algorithm S
- Knuth's power tree
- Knuth-Morris-Pratt string search
- Knuth shuffle
- Koch curve
- Kolakoski sequence
- Kosaraju
- Kronecker product
- Kronecker product based fractals
- L
- L-system
- Lagrange Interpolation
- Lah numbers
- Langton's ant
- Largest difference between adjacent primes
- Largest five adjacent number
- Largest int from concatenated ints
- Largest number divisible by its digits
- Largest palindrome product
- Largest prime factor
- Largest product in a grid
- Largest proper divisor of n
- Last Friday of each month
- Last letter-first letter
- Last list item
- Latin Squares in reduced form
- Launch rocket with countdown and acceleration in stdout
- Law of cosines - triples
- Leap year
- Least common multiple
- Least m such that n m is prime
- Left factorials
- Legendre prime counting function
- Length of an arc between two angles
- Leonardo numbers
- Letter frequency
- Levenshtein distance
- Line circle intersection
- Linear congruential generator
- Linux CPU utilization
- List comprehensions
- List rooted trees
- Literals
- Logical operations
- Logistic curve fitting in epidemiology
- Long literals with continuations
- Long multiplication
- Long primes
- Long stairs
- Long year
- Longest common prefix
- Longest common subsequence
- Longest common substring
- Longest common suffix
- Longest increasing subsequence
- Longest palindromic substrings
- Longest string challenge
- Longest substrings without repeating characters
- Look-and-say sequence
- Loop over multiple arrays simultaneously
- Loops
- LU decomposition
- Lucas-Carmichael numbers
- Lucas-Lehmer test
- Lucky and even lucky numbers
- Ludic numbers
- Luhn test of credit card numbers
- Lychrel numbers
- Lyndon word
- LZW compression
- M
- Möbius function
- MAC vendor lookup
- Machine code
- Mad Libs
- Magic 8-ball
- Magic constant
- Magic numbers
- Magic squares of doubly even order
- Magic squares of odd order
- Magic squares of singly even order
- Magnanimous numbers
- Main step of GOST 28147-89
- Make a backup file
- Make directory path
- Man or boy test
- Mandelbrot set
- Map range
- Marching squares
- Markov chain text generator
- Mastermind
- Matrix-exponentiation operator
- Matrix chain multiplication
- Matrix digital rain
- Matrix multiplication
- Matrix transposition
- Matrix with two diagonals
- Maximum difference between adjacent elements of list
- Maximum triangle path sum
- Mayan calendar
- Mayan numerals
- Maze generation
- Maze solving
- McNuggets problem
- MD4
- MD5
- Median filter
- Meissel Mertens constant
- Memory allocation
- Memory layout of a data structure
- Menu
- Merge and aggregate datasets
- Mersenne primes
- Mertens function
- Metallic ratios
- Metaprogramming
- Metered concurrency
- Metronome
- Mian-Chowla sequence
- Middle three digits
- Miller Rabin primality test
- Mind boggling card trick
- Minesweeper game
- Minimal steps down to 1
- Minimum multiple of m where digital sum equals m
- Minimum number of cells after before above and below NxN squares
- Minimum numbers of three lists
- Minimum positive multiple in base 10 using only 0 and 1
- Minimum primes
- Minkowski question-mark function
- Modified random distribution
- Modular arithmetic
- Modular exponentiation
- Modular inverse
- Modulinos
- Monads
- Monte Carlo methods
- Montgomery reduction
- Monty Hall problem
- Morse code
- Mosaic matrix
- Most frequent k chars distance
- Motzkin numbers
- Mouse position
- Move-to-front algorithm
- Multi-base primes
- Multi-dimensional array
- Multidimensional Newton-Raphson method
- Multifactorial
- Multiline shebang
- Multiple distinct objects
- Multiple regression
- Multiplication tables
- Multiplicative order
- Multiplicatively perfect numbers
- Multisplit
- Multiton
- Munchausen numbers
- Munching squares
- Musical scale
- Mutex
- Mutual recursion
- N
- N'th
- N-body problem
- N-grams
- N-queens minimum and knights and bishops
- N-queens problem
- N-smooth numbers
- Named parameters
- Names to numbers
- Naming conventions
- Narcissist
- Narcissistic decimal number
- Native shebang
- Natural sorting
- Nautical bell
- Negative base numbers
- Neighbour primes
- Nested function
- Nested templated data
- Next highest int from digits
- Next special primes
- Nice primes
- Nim game
- Nimber arithmetic
- Non-continuous subsequences
- Non-decimal radices
- Non-transitive dice
- Nonoblock
- Nonogram solver
- Nth root
- Null object
- Number names
- Number reversal game
- Numbers divisible by their individual digits but not by the product of their digits
- Numbers in base-16 representation that cannot be written with decimal digits
- Numbers in base 10 that are palindromic in bases 2 4 and 16
- Numbers k such that the last letter of k is the same as the first letter of k 1
- Numbers which are not the sum of distinct squares
- Numbers which are the cube roots of the product of their proper divisors
- Numbers whose binary and ternary digit sums are prime
- Numbers whose count of divisors is prime
- Numbers with equal rises and falls
- Numbers with prime digits whose sum is 13
- Numbers with same digit set in base 10 and base 16
- Numeric error propagation
- Numeric separator syntax
- Numerical and alphabetical suffixes
- Numerical integration
- NYSIIS
- O
- O'Halloran numbers
- Object serialization
- Odd and square numbers
- Odd squarefree semiprimes
- Odd word problem
- Odd words
- Old lady swallowed a fly
- Old Russian measure of length
- One-dimensional cellular automata
- One-time pad
- One-two primes
- One of n lines in a file
- OpenGL
- OpenWebNet password
- Operator precedence
- Optional parameters
- Orbital elements
- Order by pair comparisons
- Order disjoint list items
- Order two numerical lists
- Ordered partitions
- Ordered words
- Ormiston pairs
- Ormiston triples
- Overloaded operators
- Own digits power sum
- P
- P-Adic numbers basic
- P-value correction
- Padovan n-step number sequences
- Padovan sequence
- Pairs with common factors
- Palindrome dates
- Palindrome detection
- Palindromic gapful numbers
- Palindromic primes
- Palindromic primes in base 16
- Pan base non-primes
- Pancake numbers
- Pandigital prime
- Pangram checker
- Paraffins
- Parallel brute force
- Parallel calculations
- Parameterized SQL statement
- Parametric polymorphism
- Parse an IP Address
- Parse command-line arguments
- Parse EBNF
- Parsing
- Partial function application
- Particle fountain
- Particle swarm optimization
- Partition an integer x into n primes
- Partition function P
- Pascal's triangle
- Pascal matrix generation
- Password generator
- Pathological floating point problems
- Peaceful chess queen armies
- Peano curve
- Pell's equation
- Pell numbers
- Penholodigital squares
- Penney's game
- Penrose tiling
- Penta-power prime seeds
- Pentagram
- Pentomino tiling
- Percentage difference between images
- Perceptron
- Percolation
- Perfect numbers
- Perfect shuffle
- Perfect totient numbers
- Periodic table
- Peripheral drift illusion
- Perlin noise
- Permutation test
- Permutations
- Permutations by swapping
- Permutations with repetitions
- Permutations with some identical elements
- Permuted multiples
- Pernicious numbers
- Phrase reversals
- Pi
- Pick random element
- Pierpont primes
- Pig the dice game
- Pinstripe
- Piprimes
- Pisano period
- Plasma effect
- Playfair cipher
- Playing cards
- Plot coordinate pairs
- Pointers and references
- Poker hand analyser
- Polymorphic copy
- Polymorphism
- Polynomial derivative
- Polynomial long division
- Polynomial regression
- Polynomial synthetic division
- Polyspiral
- Population count
- Posit numbers
- Positive decimal integers with the digit 1 occurring exactly twice
- Power set
- Powerful numbers
- Practical numbers
- Pragmatic directives
- Price fraction
- Price list behind API
- Primality by trial division
- Primality by Wilson's theorem
- Prime conspiracy
- Prime decomposition
- Prime numbers p for which the sum of primes less than or equal to p is prime
- Prime numbers which contain 123
- Prime numbers whose neighboring pairs are tetraprimes
- Prime reciprocal sum
- Prime triangle
- Prime triplets
- Prime words
- Primes - allocate descendants to their ancestors
- Primes n*2 m 1
- Primes which contain only one odd digit
- Primes whose first and last number is 3
- Primes whose sum of digits is 25
- Primes with digits in nondecreasing order
- Primorial numbers
- Print debugging statement
- Print itself
- Priority queue
- Probabilistic choice
- Problem of Apollonius
- Process SMIL directives in XML data
- Product of divisors
- Product of min and max prime factors
- Program name
- Program termination
- Proof
- Proper divisors
- Pseudo-random numbers
- Pseudorandom number generator image
- Pythagoras tree
- Pythagorean quadruples
- Pythagorean triples
- Q
- R
- Radical of an integer
- Railway circuit
- Rainbow
- Ramanujan's constant
- Ramanujan primes
- Ramer-Douglas-Peucker line simplification
- Ramsey's theorem
- Random Latin squares
- Random number generator device
- Random number generator included
- Random numbers
- Random sentence from book
- Range consolidation
- Range expansion
- Range extraction
- Range modifications
- Ranking methods
- Rare numbers
- Raster bars
- Rate counter
- Ray-casting algorithm
- RCRPG
- Read a configuration file
- Read a file character by character
- Read a file line by line
- Read a specific line from a file
- Read entire file
- Readline interface
- Real constants and functions
- Recaman's sequence
- Record sound
- Recursive descent parser generator
- Reduced row echelon form
- Reflection
- Regular expressions
- Remove duplicate elements
- Remove lines from a file
- Remove vowels from a string
- Rename a file
- Rendezvous
- Rep-string
- Repeat
- Repeat a string
- Repunit primes
- Resistance calculator
- Resistance network calculator
- Resistor mesh
- Respond to an unknown method call
- Retrieve and search chat history
- Return multiple values
- Reverse a string
- Reverse the gender of a string
- Reverse the order of lines in a text file while preserving the contents of each line
- Reverse words in a string
- Rhonda numbers
- Rice coding
- Riordan numbers
- RIPEMD-160
- Robots
- Rock-paper-scissors
- Rodrigues rotation formula
- Roman numerals
- Roots of a cubic polynomial
- Roots of a function
- Roots of a quadratic function
- Roots of unity
- Rosetta Code
- Rot-13
- Round-robin tournament schedule
- RPG attributes generator
- RSA code
- Run-length encoding
- Run as a daemon or service
- Runge-Kutta method
- Runtime evaluation
- Ruth-Aaron numbers
- S
- S-expressions
- Safe addition
- Safe and Sophie Germain primes
- Safe mode
- Safe primes and unsafe primes
- Sailors coconuts and a monkey problem
- Same fringe
- Sanitize user input
- Sattolo cycle
- Scope
- Scope modifiers
- Sealed classes and methods
- Search a list
- Search a list of records
- Search in paragraph's text
- Secure temporary file
- SEDOLs
- Segmentation fault protection
- Selection bias in clinical sciences
- Selective file copy
- Selectively replace multiple instances of a character within a string
- Self-describing numbers
- Self-hosting compiler
- Self numbers
- Semiprime
- Semordnilap
- Send an unknown method call
- Send email
- SEND MORE MONEY
- Separate the house number from the street name
- Sequence nth number with exactly n divisors
- Sequence of non-squares
- Sequence of primes by trial division
- Sequence of primorial primes
- Sequence smallest number greater than previous term with exactly n divisors
- Sequence smallest number with exactly n divisors
- Set
- Set consolidation
- Set of real numbers
- Set puzzle
- Set right-adjacent bits
- Set the card game
- Seven-sided dice from five-sided dice
- Sexy primes
- SHA-1
- SHA-256
- SHA-256 Merkle tree
- Shell one-liner
- Shift list elements to left by 3
- Shoelace formula for polygonal area
- Short-circuit evaluation
- Shortest common supersequence
- Show ASCII table
- Show the decimal value of a number of 1s appended with a 3 then squared
- Show the epoch
- Sierpinski arrowhead curve
- Sierpinski carpet
- Sierpinski curve
- Sierpinski pentagon
- Sierpinski square curve
- Sierpinski triangle
- Sieve of Eratosthenes
- Sieve of Pritchard
- Simple database
- Simple windowed application
- Simulate input
- Simulated annealing
- Sine wave
- Singleton
- Singly-linked list
- Singular value decomposition
- Sisyphus sequence
- Sleep
- Sleeping Beauty problem
- Smallest enclosing circle problem
- Smallest multiple
- Smallest number k such that k 2 m is composite for all m less than k
- Smallest numbers
- Smallest power of 6 whose decimal expansion contains n
- Smallest square that begins with n
- Smarandache-Wellin primes
- Smarandache prime-digital sequence
- Smith numbers
- Snake
- Snake and ladder
- SOAP
- Sockets
- Sokoban
- Soloway's recurring rainfall
- Solve a Hidato puzzle
- Solve a Holy Knight's tour
- Solve a Hopido puzzle
- Solve a Numbrix puzzle
- Solve a Rubik's cube
- Solve equations with substitution method
- Solve hanging lantern problem
- Solve the no connection puzzle
- Solve triangle solitaire puzzle
- Sorensen Dice coefficient
- Sort a list of object identifiers
- Sort an array of composite structures
- Sort an integer array
- Sort an outline at every level
- Sort disjoint sublist
- Sort numbers lexicographically
- Sort primes from list to a list
- Sort stability
- Sort the letters of string in alphabetical order
- Sort three variables
- Sort using a custom comparator
- Sorting algorithms
- Bead sort
- Bogosort
- Bubble sort
- Circle Sort
- Cocktail sort
- Cocktail sort with shifting bounds
- Comb sort
- Counting sort
- Cycle sort
- Gnome sort
- Heapsort
- Insertion sort
- Merge sort
- Pancake sort
- Patience sort
- Permutation sort
- Quicksort
- Radix sort
- Selection sort
- Shell sort
- Sleep sort
- Stooge sort
- Strand sort
- Tree sort on a linked list
- Soundex
- Sparkline in unicode
- Special characters
- Special divisors
- Special factorials
- Special neighbor primes
- Special pythagorean triplet
- Special variables
- Speech synthesis
- Spelling of ordinal numbers
- Sphenic numbers
- Spinning rod animation
- Spiral matrix
- Split a character string based on change of character
- Spoof game
- SQL-based authentication
- Square-free integers
- Square but not cube
- Square form factorization
- Square root by hand
- Stable marriage problem
- Stack
- Stack traces
- Stair-climbing puzzle
- Start from a main routine
- Starting a web browser
- State name puzzle
- Statistics
- Steady squares
- Steffensen's method
- Stem-and-leaf plot
- Stern-Brocot sequence
- Stirling numbers of the first kind
- Stirling numbers of the second kind
- Straddling checkerboard
- Strange numbers
- Strange plus numbers
- Strange unique prime triplets
- Strassen's algorithm
- Stream merge
- String append
- String case
- String comparison
- String concatenation
- String interpolation included
- String length
- String matching
- String prepend
- Strip a set of characters from a string
- Strip block comments
- Strip comments from a string
- Strip control codes and extended characters from a string
- Strip whitespace from a string
- Strong and weak primes
- Sturmian word
- Sub-unit squares
- Subleq
- Subset sum problem
- Substitution cipher
- Substring
- Substring primes
- Subtractive generator
- Successive prime differences
- Sudan function
- Sudoku
- Suffix tree
- Suffixation of decimal numbers
- Sum and product of an array
- Sum and product puzzle
- Sum data type
- Sum digits of an integer
- Sum multiples of 3 and 5
- Sum of a series
- Sum of divisors
- Sum of elements below main diagonal of matrix
- Sum of first n cubes
- Sum of primes in odd positions is prime
- Sum of square and cube digits of an integer are primes
- Sum of squares
- Sum of the digits of n is substring of n
- Sum of two adjacent numbers are primes
- Sum to 100
- Summarize and say sequence
- Summarize primes
- Summation of primes
- Sunflower fractal
- Super-d numbers
- Super-Poulet numbers
- Superellipse
- Superpermutation minimisation
- Sutherland-Hodgman polygon clipping
- Sylvester's sequence
- Symmetric difference
- Sync subtitles
- Synchronous concurrency
- System time
- Szymański's algorithm
- T
- Table creation
- Take notes on the command line
- Tarjan
- Tau function
- Tau number
- Taxicab numbers
- Teacup rim text
- Temperature conversion
- Terminal control
- Ternary logic
- Test a function
- Test integerness
- Text between
- Text completion
- Text processing
- Text to HTML
- Textonyms
- The ISAAC cipher
- The Name Game
- The sieve of Sundaram
- The Twelve Days of Christmas
- Thiele's interpolation formula
- Three word location
- Thue-Morse
- Tic-tac-toe
- Time-based one-time password algorithm
- Time a function
- Tokenize a string
- Tokenize a string with escaping
- Tonelli-Shanks algorithm
- Top rank per group
- Topic variable
- Topological sort
- Topswops
- Total circles area
- Totient function
- Towers of Hanoi
- Trabb Pardo Knuth algorithm
- Transliterate English text using the Greek alphabet
- Transportation problem
- Tree datastructures
- Tree from nesting levels
- Tree traversal
- Triangular numbers
- Trigonometric functions
- Triplet of three numbers
- Tropical algebra overloading
- Truncatable primes
- Truncate a file
- Truth table
- Twelve statements
- Twin primes
- Two's complement
- Two bullet roulette
- Two identical strings
- Two sum
- Type detection
- U
- Ulam numbers
- Ulam spiral for primes
- Ultra useful primes
- Unbias a random generator
- Undefined values
- Undulating numbers
- Unicode strings
- Unicode variable names
- Unique characters
- Unique characters in each string
- Unit testing
- Universal Turing machine
- Unix
- Unprimeable numbers
- Untouchable numbers
- Untrusted environment
- UPC
- Update a configuration file
- Upside-down numbers
- URL decoding
- URL encoding
- URL parser
- URL shortener
- Use another language to call a function
- Useless instructions
- User defined pipe and redirection operators
- User input
- Using a speech engine to highlight words
- UTF-8 encode and decode
- V
- Validate International Securities Identification Number
- Vampire number
- Van der Corput sequence
- Van Eck sequence
- Variable-length quantity
- Variable declaration reset
- Variable size
- Variables
- Variadic function
- Vector
- Vector products
- Verhoeff algorithm
- Verify distribution uniformity
- Vibrating rectangles
- Video display modes
- Vidir
- Vigenère cipher
- Visitor pattern
- Visualize a tree
- VList
- Vogel's approximation method
- Voronoi diagram
- W
- Wagstaff primes
- Walk a directory
- Walsh matrix
- War card game
- Wasteful equidigital and frugal numbers
- Water collected between towers
- Wave function collapse
- Waveform analysis
- Web scraping
- Weird numbers
- Welch's t-test
- Wieferich primes
- WiktionaryDumps to words
- Wilson primes of order n
- Window creation
- Window management
- Wireworld
- Wolstenholme numbers
- Word break problem
- Word frequency
- Word ladder
- Word search
- Word wheel
- Word wrap
- Wordiff
- Wordle comparison
- Words containing the substring
- Words from neighbour ones
- World Cup group stage
- Worthwhile task shaving
- Write entire file
- Write float arrays to a text file
- Write language name in 3D ASCII
- Write to Windows event log
- X
- Y
- Z
- The End