# 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
- Canonicalize CIDR
- 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
- Colour pinstripe/Printer
- Commatizing numbers
- Compare sorting algorithms' performance
- Compiler/AST interpreter
- Compiler/code generator
- Compiler/syntax analyzer
- Compiler/virtual machine interpreter
- Consecutive primes with ascending or descending dfferences
- Convex hull
- Create a file on magnetic tape
- Create an object at a given address
- Currency
- Cyclotomic polynomial

### D

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

### E

- EKG sequence convergence
- 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
- Esthetic numbers
- Events
- Executable library
- 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
- Factorions
- 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 Chess960 starting position identifier
- Find common directory path
- Find duplicate files
- Find largest left truncatable prime in a given base
- Find the intersection of a line with a plane
- Find the intersection of two lines
- 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
- Floyd-Warshall algorithm
- 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
- Long year
- Longest string challenge
- Lucky and even lucky numbers

### M

- Mad Libs
- Magic 8-ball
- 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 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-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
- Parametrized SQL statement
- Parse an IP Address
- 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
- Pentagram
- Percolation/Bond percolation
- Percolation/Mean cluster density
- Percolation/Mean run density
- Percolation/Site percolation
- Perfect totient numbers
- 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
- Primes - allocate descendants to their ancestors
- Problem of Apollonius
- Pseudo-random numbers/Combined recursive generator MRG32k3a
- 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
- Resistor mesh
- Retrieve and search chat history
- 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

### 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
- Secure temporary file
- 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
- Sexy primes
- Shoelace formula for polygonal area
- Shortest common supersequence
- Sierpinski arrowhead curve
- Sierpinski pentagon
- Sierpinski square curve
- Sierpinski triangle/Graphical
- Simulate input/Keyboard
- Sleeping Beauty problem
- Smarandache prime-digital sequence
- Smith numbers
- 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
- Suffixation of decimal numbers
- 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 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

### B

### C

- CLI-based maze-game
- Card shuffles
- Change e letters to i in words
- Changeable words
- Chebyshev coefficients
- Checksumcolor
- Chemical calculator
- Chess player
- Cipolla's algorithm
- Code segment unload
- Combinations with repetitions/Square digit chain
- Common list elements
- Common sorted list
- 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 how many vowels and consonants occur in a string
- Count the coins/0-1
- Cousin primes
- Create an object/Native demonstration
- Cubic Special Primes
- Curve that touches three points
- Cycle detection
- Cyclops numbers

### D

- Data Encryption Standard
- Days between dates
- Decimal floating point number to binary
- Decision tables
- Discrete Fourier transform
- Distinct Palindromes within decimal numbers
- Distinct power numbers
- Distribution of 0 Digits in factorial series
- Doomsday rule
- Doubly-linked list/Element removal
- Draw pixel 2

### F

- Fibonacci heap
- Fibonacci matrix-exponentiation
- Find URI in text
- 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 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
- Free polyominoes enumeration
- Frobenius numbers

### G

### I

### L

- 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
- Longest common prefix
- Longest common suffix
- Longest palindromic substrings
- Longest substrings without repeating characters

### M

- Markov chain text generator
- Maximum difference between adjacent elements of list
- Mersenne primes
- Mine a bitcoin
- Minimum number of cells after, before, above and below NxN squares
- Montgomery reduction
- Morpion solitaire
- Most frequent k chars distance
- Multi-base primes
- Multidimensional Newton-Raphson method
- Multiton

### N

- N-body problem
- NYSIIS
- Native shebang
- Neighbour primes
- Next special primes
- Nice primes
- 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
- Pandigital prime
- Parse EBNF
- Parse command-line arguments
- Particle fountain
- Particle swarm optimization
- Penrose tiling
- Pentomino tiling
- Perceptron
- Peripheral drift illusion
- Permutations with repetitions
- Permutations with some identical elements
- Permuted multiples
- Piprimes
- Polynomial synthetic division
- Positive decimal integers with the digit 1 occurring exactly twice
- Powerful numbers
- Practical numbers
- Price list behind API
- Prime numbers p which sum of prime numbers less or equal to p is prime
- Prime numbers which contain 123
- Prime triplets
- Prime words
- Primes which contain only one odd digit
- Primes which sum of digits is 25
- Primes whose first and last number is 3
- Primes with digits in nondecreasing order
- 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
- 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
- Rosetta Code/List authors of task descriptions
- Rosetta Code/Run examples
- Rosetta Code/Tasks without examples
- Run as a daemon or service

### S

- Safe mode
- Sattolo cycle
- 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
- Simple turtle graphics
- Simulated annealing
- Sine wave
- Singly-linked list/Element removal
- Smallest enclosing circle problem
- Smallest numbers
- Smallest power of 6 whose decimal expansion contains n
- Smallest square that begins with n
- Snake
- Snake and Ladder
- Solve a Rubik's Cube
- Solve triangle solitare puzzle
- Solving coin problems
- Sort the letters of string in alphabetical order
- Sorting algorithms/Cycle sort
- Sorting algorithms/Tree sort on a linked list
- Special Divisors
- Special factorials
- Special neighbor primes
- Special pythagorean triplet
- Spoof game
- Square root by hand
- Starting a web browser
- Strange numbers
- Strange plus numbers
- Strange unique prime triplets
- Subset sum problem
- Substring primes
- Suffix tree
- Sum data type
- Sum of elements below main diagonal of matrix
- Sum of first n cubes
- Sum of primes in odd positions is prime
- Sum of the digits of n is substring of n
- Sunflower fractal

### T

- Table creation
- Tamagotchi emulator
- Tetris
- Text between
- Text completion
- Text to HTML
- Three word location
- Time-based one-time password algorithm
- Topological sort/Extracted top item
- 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.