# Reports:Tasks not implemented in Common Lisp

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## Contents

## Not implemented[edit]

These are currently not implemented in Common Lisp. Please implement some if you can. If any tasks are not possible or too complex in Common Lisp, they should not be on this list. To mark a task as such, add **{{omit from|Common Lisp}}**, preserving the capitalization of the language, to that task. It will appear below under the "Not Considered" section.

### 2

### A

### B

### C

- Calkin-Wilf sequence
- Canny edge detector
- Cantor set
- Carmichael 3 strong pseudoprimes
- Catmull–Clark subdivision surface
- Chaocipher
- Check Machin-like formulas
- Checkpoint synchronization
- Chernick's Carmichael numbers
- Chowla numbers
- Church numerals
- Circles of given radius through two points
- Circular primes
- Cistercian numerals
- Color wheel
- Colorful numbers
- Colour pinstripe/Printer
- Commatizing numbers
- Compare length of two strings
- Compare sorting algorithms' performance
- Compiler/AST interpreter
- Compiler/code generator
- Composite numbers k with no single digit factors whose factors are all substrings of k
- Consecutive primes with ascending or descending differences
- Create a file on magnetic tape
- Create an object at a given address
- Cullen and Woodall numbers
- Currency
- Curzon numbers
- Cyclops numbers
- Cyclotomic polynomial

### D

- Damm algorithm
- Date manipulation
- De Bruijn sequences
- Death Star
- Deceptive numbers
- Deconvolution/2D+
- Deming's funnel
- Department numbers
- Descending primes
- Determine if a string is collapsible
- Determine if a string is squeezable
- Determine if only one instance is running
- Determine if two triangles overlap
- Determine sentence type
- Dice game probabilities
- Disarium numbers
- Discordian date
- Display a linear combination
- Display an outline as a nested table
- Distributed programming
- Diversity prediction theorem
- Dominoes
- Doubly-linked list/Traversal
- Draw a clock
- Draw a cuboid
- Draw a pixel
- Draw a rotating cube
- Duffinian numbers
- Dutch national flag problem

### E

- EKG sequence convergence
- Earliest difference between prime gaps
- Eban numbers
- Eertree
- Elementary cellular automaton/Infinite length
- Elementary cellular automaton/Random number generator
- Elliptic Curve Digital Signature Algorithm
- Elliptic curve arithmetic
- Enforced immutability
- Entropy/Narcissist
- Equal prime and composite sums
- Erdös-Selfridge categorization of primes
- Esthetic numbers
- Euler's constant 0.5772...
- Events
- Executable library
- Execute Computer/Zero
- Execute SNUSP
- Exponentiation with infix operators in (or operating on) the base
- Extensible prime generator
- Extreme floating point values

### F

- Faces from a mesh
- Factorial base numbers indexing permutations of a collection
- Fairshare between two and more
- Faulhaber's formula
- Faulhaber's triangle
- Feigenbaum constant calculation
- Fibonacci word/fractal
- File extension is in extensions list
- File size distribution
- Find duplicate files
- Find largest left truncatable prime in a given base
- Find the intersection of a line with a plane
- First class environments
- First perfect square in base n with n unique digits
- First power of 2 that has leading decimal digits of 12
- Fivenum
- Fixed length records
- Flipping bits game
- Flow-control structures
- Fortunate numbers
- Four is the number of letters in the ...
- Fraction reduction
- French Republican calendar
- Functional coverage tree
- Fusc sequence

### G

### H

### I

### J

### K

### L

- Lah numbers
- Largest number divisible by its digits
- Largest proper divisor of n
- Latin Squares in reduced form
- Latin Squares in reduced form/Randomizing using Jacobson and Matthews’ Technique
- Law of cosines - triples
- Legendre prime counting function
- Levenshtein distance/Alignment
- List rooted trees
- Long literals, with continuations
- Longest string challenge
- Lucky and even lucky numbers

### M

- Mad Libs
- Magic 8-ball
- Magic constant
- Magic squares of doubly even order
- Magic squares of singly even order
- Magnanimous numbers
- Main step of GOST 28147-89
- Mastermind
- Matrix chain multiplication
- Mayan calendar
- Mayan numerals
- Maze solving
- McNuggets problem
- Median filter
- Memory layout of a data structure
- Merge and aggregate datasets
- Mertens function
- Metallic ratios
- Metered concurrency
- Mian-Chowla sequence
- Mind boggling card trick
- Minimal steps down to 1
- Minimum multiple of m where digital sum equals m
- Minimum positive multiple in base 10 using only 0 and 1
- Minkowski question-mark function
- Modified random distribution
- Modular arithmetic
- Monads/List monad
- Monads/Maybe monad
- Monads/Writer monad
- Morse code
- Motzkin numbers
- Multi-base primes
- Multi-dimensional array
- Multiplicative order
- Multisplit
- Munching squares
- Musical scale
- Mutex
- Möbius function

### N

### O

### P

- P-Adic numbers, basic
- P-Adic square roots
- P-value correction
- Padovan n-step number sequences
- Padovan sequence
- Palindrome dates
- Palindromic gapful numbers
- Pancake numbers
- Paraffins
- Parameterized SQL statement
- Parse an IP Address
- Particle fountain
- Partition an integer x into n primes
- Partition function P
- Pascal's triangle/Puzzle
- Pathological floating point problems
- Peaceful chess queen armies
- Peano curve
- Pell's equation
- Pell numbers
- Pentagram
- Pentomino tiling
- Percolation/Bond percolation
- Percolation/Mean cluster density
- Percolation/Mean run density
- Percolation/Site percolation
- Perfect totient numbers
- Periodic table
- Peripheral drift illusion
- Permutations/Derangements
- Permutations/Rank of a permutation
- Pierpont primes
- Pinstripe/Display
- Pinstripe/Printer
- Pisano period
- Play recorded sounds
- Playfair cipher
- Plot coordinate pairs
- Poker hand analyser
- Polyspiral
- Prime conspiracy
- Prime triangle
- Primes - allocate descendants to their ancestors
- Problem of Apollonius
- Pseudo-random numbers/Combined recursive generator MRG32k3a
- Pseudo-random numbers/Middle-square method
- Pseudo-random numbers/PCG32
- Pseudo-random numbers/Splitmix64
- Pseudo-random numbers/Xorshift star
- Pythagoras tree
- Pythagorean quadruples

### R

- Ramanujan's constant
- Ramanujan primes/twins
- Ramer-Douglas-Peucker line simplification
- Random Latin squares
- Random sentence from book
- Range consolidation
- Ranking methods
- Rare numbers
- Recaman's sequence
- Reflection/Get source
- Reflection/List methods
- Reflection/List properties
- Rendezvous
- Repunit primes
- Resistor mesh
- Retrieve and search chat history
- Rhonda numbers
- Rock-paper-scissors
- Rosetta Code/Count examples
- Rosetta Code/Find bare lang tags
- Rosetta Code/Find unimplemented tasks
- Rosetta Code/Fix code tags
- Rosetta Code/Rank languages by number of users
- Rosetta Code/Rank languages by popularity
- Ruth-Aaron numbers

### S

- SHA-256 Merkle tree
- SOAP
- SQL-based authentication
- Safe addition
- Safe primes and unsafe primes
- Sailors, coconuts and a monkey problem
- Same fringe
- Scope/Function names and labels
- Search in paragraph's text
- Secure temporary file
- Selectively replace multiple instances of a character within a string
- Self numbers
- Send email
- Sequence: nth number with exactly n divisors
- Sequence: smallest number greater than previous term with exactly n divisors
- Sequence: smallest number with exactly n divisors
- Sequence of primorial primes
- Set puzzle
- Set right-adjacent bits
- Sexy primes
- Shoelace formula for polygonal area
- Shortest common supersequence
- Sierpinski arrowhead curve
- Sierpinski pentagon
- Sierpinski square curve
- Sierpinski triangle/Graphical
- Simple turtle graphics
- Simulate input/Keyboard
- Sleeping Beauty problem
- Smallest number k such that k+2^m is composite for all m less than k
- Smarandache prime-digital sequence
- Smith numbers
- Snake
- Sokoban
- Solve a Hidato puzzle
- Solve a Holy Knight's tour
- Solve a Hopido puzzle
- Solve a Numbrix puzzle
- Solve the no connection puzzle
- Sort an outline at every level
- Sort three variables
- Sorting Algorithms/Circle Sort
- Sorting algorithms/Cocktail sort with shifting bounds
- Sorting algorithms/Patience sort
- Sorting algorithms/Radix sort
- Special characters
- Speech synthesis
- Spinning rod animation/Text
- Square-free integers
- Square form factorization
- Stable marriage problem
- Start from a main routine
- State name puzzle
- Statistics/Basic
- Statistics/Normal distribution
- Stem-and-leaf plot
- Stirling numbers of the first kind
- Stirling numbers of the second kind
- Straddling checkerboard
- Strassen's algorithm
- Stream merge
- Strip block comments
- Strong and weak primes
- Substitution cipher
- Successive prime differences
- Sudan function
- Suffixation of decimal numbers
- Sum of elements below main diagonal of matrix
- Summarize primes
- Super-d numbers
- Superellipse
- Superpermutation minimisation
- Sutherland-Hodgman polygon clipping
- Sylvester's sequence

### T

- Table creation/Postal addresses
- Tarjan
- Tau function
- Tau number
- Taxicab numbers
- Teacup rim text
- Test integerness
- Text processing/2
- Textonyms
- The Name Game
- The sieve of Sundaram
- Tonelli-Shanks algorithm
- Topic variable
- Topswops
- Total circles area
- Totient function
- Tree datastructures
- Tree from nesting levels
- Truncate a file
- Truth table
- Twin primes
- Two's complement
- Two bullet roulette

### U

### V

### W

### Draft tasks without implementation[edit]

These tasks are drafts, meaning they largely need more work to turn them into full tasks. Perhaps you can help by trying to implement them in Common Lisp (after all, one of the key requirements for a task being non-draft is multiple implementations, preferably in widely different languages) but be aware that this may be difficult because of lack of definition of the task itself.

### A

- ABC words
- ADFGVX cipher
- Addition-chain exponentiation
- Addition chains
- Air mass
- Alternade words
- Anadromes
- Anagram generator
- Append numbers at same position in strings
- Arithmetic coding/As a generalized change of radix
- Arithmetic derivative
- Assertions in design by contract
- Audio alarm
- Audio frequency generator
- Audio overlap loop
- Autogram checker

### B

- B-spline
- Babylonian spiral
- Banker's algorithm
- Base58Check encoding
- Base 16 numbers needing a to f
- Bifid cipher
- Bilinear interpolation
- Binary coded decimal
- Bioinformatics/Global alignment
- Bioinformatics/Subsequence
- Birthday problem
- Black box
- Blackjack strategy
- Boids
- Boyer-Moore string search
- Brace expansion using ranges

### C

- CLI-based maze-game
- Camel case and snake case
- Card shuffles
- Change e letters to i in words
- Changeable words
- Chebyshev coefficients
- Checksumcolor
- Chemical calculator
- Chess player
- Cipolla's algorithm
- Code Golf: Code Golf
- Code segment unload
- Collect and sort square numbers in ascending order from three lists
- Combinations with repetitions/Square digit chain
- Common list elements
- Common sorted list
- Compiler/Preprocessor
- Compiler/Simple file inclusion pre processor
- Compiler/Verifying syntax
- Concatenate two primes is also prime
- Conjugate a Latin verb
- Continued fraction/Arithmetic/G(matrix ng, continued fraction n)
- Continued fraction/Arithmetic/G(matrix ng, continued fraction n1, continued fraction n2)
- Coprime triplets
- Coprimes
- Count the coins/0-1
- Cousin primes
- Create an executable for a program in an interpreted language
- Create an object/Native demonstration
- Create your own text control codes
- Cross compilation
- Cubic special primes
- Curve that touches three points
- Cycle detection
- Cycles of a permutation

### D

- Data Encryption Standard
- Dating agency
- Day of the week of Christmas and New Year
- Days between dates
- Decimal floating point number to binary
- Decision tables
- Digit fifth powers
- Diophantine linear system solving
- Discrete Fourier transform
- Distinct palindromes within decimal numbers
- Distinct power numbers
- Distribution of 0 digits in factorial series
- Divide a rectangle into a number of unequal triangles
- Doomsday rule
- Doubly-linked list/Element removal
- Draw pixel 2

### E

### F

- Factorial primes
- Fibonacci heap
- Fibonacci matrix-exponentiation
- Find URI in text
- Find adjacent primes which differ by a square integer
- Find first and last set bit of a long integer
- Find first missing positive
- Find minimum number of coins that make a given value
- Find prime n such that reversed n is also prime
- Find prime numbers of the form n*n*n+2
- Find square difference
- Find squares n where n+1 is prime
- Find words which contain the most consonants
- 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 9 prime Fibonacci number
- Four sides of square
- Free polyominoes enumeration
- Frobenius numbers

### G

### I

### L

- Largest difference between adjacent primes
- Largest five adjacent number
- Largest palindrome product
- Largest prime factor
- Largest product in a grid
- Last list item
- Launch rocket with countdown and acceleration in stdout
- Length of an arc between two angles
- Line circle intersection
- Linux CPU utilization
- Logistic curve fitting in epidemiology
- Long stairs
- Longest common prefix
- Longest common suffix
- Longest palindromic substrings
- Longest substrings without repeating characters

### M

- Marching squares
- Markov chain text generator
- Matrix with two diagonals
- Maximum difference between adjacent elements of list
- Mersenne primes
- Minimum number of cells after, before, above and below NxN squares
- Minimum numbers of three lists
- Minimum primes
- Montgomery reduction
- Morpion solitaire
- Mosaic matrix
- Most frequent k chars distance
- Multidimensional Newton-Raphson method
- Multiton

### N

- N-body problem
- N-queens minimum and knights and bishops
- NYSIIS
- Native shebang
- Neighbour primes
- Next special primes
- Nice primes
- Nimber arithmetic
- Number triplets 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 which binary and ternary digit sum are prime
- Numbers whose count of divisors is prime
- Numbers with prime digits whose sum is 13
- Numbers with same digit set in base 10 and base 16
- Numeric separator syntax
- Numerical integration/Adaptive Simpson's method

### O

### P

- Palindromic primes
- Palindromic primes in base 16
- Pan base non-primes
- Pandigital prime
- Parse EBNF
- Parse command-line arguments
- Particle swarm optimization
- Penrose tiling
- Perceptron
- Permutations with repetitions
- Permutations with some identical elements
- Permuted multiples
- Piprimes
- Polynomial derivative
- Polynomial synthetic division
- Positive decimal integers with the digit 1 occurring exactly twice
- Powerful numbers
- Practical numbers
- Price list behind API
- Prime numbers p for which the sum of primes less than or equal to p is prime
- Prime numbers which contain 123
- Prime triplets
- Prime words
- 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 primes
- Print debugging statement
- Print itself
- Process SMIL directives in XML data
- Proof
- Pseudorandom number generator image

### R

- Railway circuit
- Ramanujan primes
- Ramsey's theorem
- Range modifications
- Raster bars
- Readline interface
- Recursive descent parser generator
- Red black tree sort
- Remote agent/Agent interface
- Remote agent/Agent logic
- Remote agent/Simulation
- Resistance calculator
- Resistance network calculator
- Reverse the gender of a string
- Reverse the order of lines in a text file while preserving the contents of each line
- Rodrigues’ rotation formula
- Rosetta Code/List authors of task descriptions
- Rosetta Code/Run examples
- Rosetta Code/Tasks without examples
- Round-robin tournament schedule
- Run as a daemon or service

### S

- Safe and Sophie Germain primes
- Safe mode
- Sanitize user input
- Sattolo cycle
- Segmentation fault protection
- Selective file copy
- Self-hosting compiler
- Separate the house number from the street name
- Show the (decimal) value of a number of 1s appended with a 3, then squared
- Sierpinski curve
- Simulated annealing
- Sine wave
- Singly-linked list/Element removal
- Smallest enclosing circle problem
- Smallest multiple
- Smallest numbers
- Smallest power of 6 whose decimal expansion contains n
- Smallest square that begins with n
- Snake and ladder
- Solve a Rubik's cube
- Solve equations with substitution method
- Solve hanging lantern problem
- Solve triangle solitare puzzle
- Solving coin problems
- Sort primes from list to a list
- Sorting algorithms/Cycle sort
- Sorting algorithms/Tree sort on a linked list
- Special divisors
- Special factorials
- Special neighbor primes
- Spoof game
- Square root by hand
- Starting a web browser
- Steady squares
- Strange numbers
- Strange plus numbers
- Strange unique prime triplets
- Subset sum problem
- Substring primes
- Suffix tree
- Sum data type
- 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 the digits of n is substring of n
- Sum of two adjacent numbers are primes
- Summation of primes
- Sunflower fractal

### T

- Table creation
- Tetris
- Text between
- Text completion
- Text to HTML
- Three word location
- Time-based one-time password algorithm
- Topological sort/Extracted top item
- Transliterate English text using the Greek alphabet
- Transportation problem
- Triplet of three numbers
- Tropical algebra overloading
- Two identical strings
- Two sum
- Type detection

### U

### W

## Requiring Attention[edit]

### Examples[edit]

These tasks have implementations in Common Lisp, but somebody, somewhere, decided that the example implementation was faulty or in some other way requiring attention. If you're familiar with the task and language, please consider reviewing/correcting the example and removing the notice.

### Other pages[edit]

These are other pages related to Common Lisp which require attention; with your knowledge and assistance, we can improve the quality of the site's content.

### No pages found.

## Not Considered[edit]

These tasks are not generally counted toward "unimplemented", as somebody, somewhere, decided that Common Lisp was inappropriate for these tasks, or implementations of them would be unenlightening. Feel free to try your hand at them anyway.

### No pages found.

## End of List[edit]

Again, feel free to try your hand at any of the tasks listed on this page.