CodeEval (Defunct) Problem Statements

As of 2018-02-12, CodeEval has ceased operations. This (unofficial) repository mirrors* the problem statements for all 239‡ interactive challenges that once lived on the platform.

^{* A couple of problem statements are missing animated GIFs which I don't have a backup of. They were supplementary and are not required to solve the challenges in question.}

^{‡ Technically, there were 240 challenges on the platform. Challenge #127 ("Code Plagiarism") wasn't an interactive/graded challenge; thus no points were awarded for it by the online evaluation system.}

Easy (35 Points)

CID	Name	Synopsis
152	Age Distribution	Print out where the person is
082	Armstrong Numbers	Determine if a number is an armstrong number
083	Beautiful Strings	Facebook Hacker Cup 2013 problem
163	Big Digits	Print out magnified digits using pseudographics
019	Bit Positions	Bits in position x,y are same or different
222	Black Card	Find the winner
099	Calculate Distance	Calculate a distance between two points
093	Capitalize Words	Capitalize words in a sentence
211	Chardonnay or Cabernet	Guess a wine name
205	Clean Up the Words	Print the words separated by spaces
192	Compare Points	Given two (x, y) points A and B, determine which cardinal direction B is from A
128	Compressed Sequence	Write a program that compresses a sequence of numbers
140	Data Recovery	Reconstruct a sentence using hints
166	Delta Time	Find the time difference
183	Details	Determine how many cells will be shifted detail
100	Even Numbers	Determine if a number is even or not
022	Fibonacci Series	Print out the nth fibonacci number
026	File Size	Print the file size in bytes
097	Find a Writer	Find a famous writer in a string
208	Find the Highest Score	Find the highest rate in the table
001	Fizz Buzz	A simple game involving divisibility tests
230	Football	Find countries that are football fans
039	Happy Numbers	Determine if a number is a happy number or not
067	Hex to Decimal	Convert a hex number to it's decimal equivalent
122	Hidden Digits	Try to look behind the scenes
102	JSON Menu IDs	Calculate IDs in JSON menu
149	Juggling With Zeros	Convert a zero-based number into integer
180	Knight Moves	Find positions for the next move of the knight
147	Lettercase Percentage Ratio	Find the percentage ratio
111	Longest Word	Get the longest word in a sentence
020	Lowercase	Lowercase text
103	Lowest Unique Number	Find the lowest unique number in a set
178	Matrix Rotation	Rotate a 2D matrix 90 degrees clockwise
186	Max Range Sum	Determine max sum at the range
240	Mersenne Prime	Find all Mersenne numbers smaller than n
189	Minimum Distance	Find a point with the smallest sum of distances to every given point
115	Mixed Content	Separate words with digits
116	Morse Code	Decode Morse code
018	Multiples of a Number	Multiples of a number greater than another number
023	Multiplication Tables	Print out the grade school multiplication table upto 12*12
113	Multiply Lists	Multiply elements in 2 lists
062	N Mod M	Determine the modulus (without the modulus operator)
160	Nice Angles	Convert angle values to sexagesimal format
232	Not So Clever	Simplicity is not always good
025	Odd Numbers	Print the odd numbers from 1 to 99
217	One Zero, Two zeros...	Count zeros in a binary system
237	Panacea - Truth or Lie	Check whether the virus was stopped by antivirus
092	Penultimate Word	Find the next-to-last word
003	Prime Palindrome	Biggest prime palindrome < 1000
087	Query Board	Set and get values from a matrix using tiny DSL
136	Racing Chars	Explore a race track avoiding crashes
167	Read More	Limit the length of the text
227	Real Fake	Check credit card numbers
008	Reverse Words	Reversing an input sequence of words
031	Rightmost Char	Print the position of the rightmost occurrence of a char
124	Road Trip	Do not be left without petrol
156	Roller Coaster	Turn the text into RoLlErCoAsTeR case
106	Roman Numerals	Convert a cardinal number to a Roman numeral
040	Self Describing Numbers	Determine if a number is a self-describing number or not
030	Set Intersection	Print the intersection of two sets of numbers
107	Shortest Repetition	Find the shortest repetition in a string
235	Simple or Trump	Check which card is higher
091	Simple Sorting	Sort several numbers
174	Slang Flavor	Add some slang to the text
131	Split the Number	Evaluate the number according to the pattern
202	Stepwise Word	Print the longest word in a stepwise manner
199	String Mask	Change case letters by mask
203	Strings and Arrows	Print the number of arrows in a string
021	Sum of Digits	Sum of digits comprising a number
024	Sum of Integers From File	Print the sum of integers read from a file
004	Sum of Primes	Sum of first 1000 primes
096	Swap Case	Swap case in a string
112	Swap Elements	Swap elements in a list
196	Swap Numbers	Swap numbers surrounding a word
225	Testing	Wanna try to be a tester?
132	The Major Element	Find the major element in a sequence
214	Time to Eat	Sort timestamps in the right order
220	Trick or Treat	Count all candies
029	Unique Elements	Extract unique list from a sorted list of numbers
173	Without Repetitions	Delete characters that are consistently repeated
104	Word to Digit	Substitute words to digits
139	Working Experience	Retrieve an actual value

Moderate (65 Points)

CID	Name	Synopsis
117	A Pile of Bricks	Close a hole in a wall
223	Alternative Reality	Count all alternative ways
041	Array Absurdity	Determine if an array contains a duplicated entry
084	Balanced Smileys	Facebook Hacker Cup 2013 problem
146	Bats Challenge	Count bats on the wire
236	Beat or Bit	Learn more about the Gray code algorithm
209	Black or White	Find the smallest submatrix
179	Broken LCD	Determine whether a given number can be displayed on the damaged LCD
218	Builders Team	Count all squares on the map
184	Burrows-Wheeler Transform	Complete file decompression by inverting BWT
138	Car Race	Determine the fastest car
172	Card Number Validation	Check if bank card numbers are valid
054	Cash Register	Determine the amount of change to be returned
119	Chain Inspection	Try to pass a chain
133	City Blocks Flyover	Chart the path of a helicopter from above to discover how many city blocks it flew over
238	Code Combinations	Check whether you can make words from the given letters
148	Color Code Converter	Determine and convert the color code
197	Column Names	Convert integer to excel-style column name
187	Consecutive Primes	Determine how many ways the numbers can be arranged such that every consecutive pair sums to a prime
063	Counting Primes	Count the number of primes between two integers
027	Decimal to Binary	Print the binary representation of a decimal number
073	Decode Numbers	Count the number of ways to decode a string
005	Detecting Cycles	Detecting loops within a sequence
033	Double Squares	FaceBook Hacker Cup 2011: Output the number of ways to write X as the sum of two squares
215	Double Trouble	Calculate the number of correct variants for messages
035	Email Validation	Write a regular expression to validate an email address
015	Endianness	Determine the endianness of a system
169	Filename Pattern	Filter a list of filenames
101	Find a Square	Do 4 points make a square?
012	First Non-Repeated Character	Find the first non repeated character in a string
075	Flavius Josephus	Eliminate every i'th item from a circular list
161	Game of Life	Implement the classical cellular automaton game
181	Gronsfeld Cipher	Decipher the message enciphered with the Gronsfeld cipher
170	Guess the Number	Guess the number in log2(N) steps
158	Interrupted Bubble Sort	Sort a list of elements, partially
043	Jolly Jumpers	Determine if a sequence of numbers is a Jolly Jumper
177	Justify the Text	Align the text to the specified width
153	Locks	Calculate unlocked doors
002	Longest Lines	Finding the 'N' longest lines within a file
121	Lost in Translation	Try to become a native speaker
011	Lowest Common Ancestor	Determine the lowest common ancestor within a tree
206	Lucky Tickets	Count the lucky tickets
193	Magic Numbers	Print out a list of all the magic numbers in a provided range
231	Meet Cocktail Sort	Learn more about cocktail sort algorithm
233	Meet Comb Sort	Learn more about the comb sort algorithm
074	Minimum Coins	Find the minimum number of coins to arrive at a total
010	Mth to Last Element	Determine the Mth to last element of a list
016	Number of Ones	Determine the number of one bits in an integer
190	Number Operations	Determine if it is possible to produce the number 42 with five cards
034	Number Pairs	Find pairs of numbers in a sorted array whose sum is X
221	Organizational Hierarchy	Recreate the hierarchy tree
070	Overlapping Rectangles	Determine if two rectangles overlap
037	Pangrams	Find the missing alphabets
066	Pascals Triangle	Print out pascals triangle upto a certain depth
089	Pass Triangle	Lead the way within the triangle
098	Point in Circle	Define whether a point is in a circle
125	Predict the Number	Try to go beyond the limits
046	Prime Numbers	Print prime numbers less than N
013	Remove Characters	Delete specific characters from a string
045	Reverse and Add	Continually add a number to its reverse to arrive at a palindrome
071	Reverse Groups	Reverse elements in a list k items at a time
212	Robo and Robitta	Count all nuts
150	Roman and Arabic	Calculate aromatic numbers
137	Seek for an Intruder	Find the IP address of an intruder
130	Sequence Transformation	Transform a binary sequence into a string
094	Simple Calculator	Create a simple calculator
200	Sort Matrix Columns	Sort matrix columns from lowest to highest numbers
009	Stack Implementation	Implement a stack interface
076	String Rotation	Find if a string is the rotation of another string
078	Sudoku	Determine if a grid layout is a valid sudoku solution
165	Suggest Groups	Help your friends to join groups
017	Sum of Integers	Determine the largest sum of contiguous integers in an array
081	Sum to Zero	Count of ways in which the sum of four numbers is zero
143	The Ministry of Truth	Your task is to help the Big Brother
228	To PI or Not to PI	Print a PI number
032	Trailing String	Determine if a string 'B' occurs at the end of string 'A'
226	Try to Solve It	How good decoder are you?
194	Twenty Forty Eight	Implement the 2048 game logic
080	URI Comparison	Determine if two URIs match
068	Valid Parentheses	Determine if string is a well-formed parentheses
135	Word Chain	Find the longest chain of words

Hard (100 Points)

CID	Name	Synopsis
134	A Bus Network	Try to save more time
095	Advanced Calculator	Create an advanced calculator
201	Alphabet Blocks	Forming words from alphabet blocks
239	As Quick as a Flash	Learn more about the quick sort algorithm
155	ASCII Decryption	Decrypt a message
109	Bay Bridges	Build Bridges Over San Francisco Bay
210	Brainf*ck	Blow your mind
064	Climbing Stairs	Count the number of ways to climb to the top of a staircase
051	Closest Pair	Given a set of points in a two dimensional space, you will have to find the distance between the closest two points
234	Code Like Huffman	Learn more about Huffman's tree
127	Code Plagiarism	Compare source code of two programs
090	Commuting Engineer	Travelling Salesman Problem
108	Computer Terminal	Print text to terminal with control sequences
151	Cracking Eggs	Determine the number of drops
195	Crime House	Count criminals in the Crime House
077	Da Vyncy	Recreate a document from a set of fragments
061	Decryption	Determine the plain text message from an encrypted string
144	Digit Statistics	Find statistics in sequence
048	Discount Offers	Determine optimal pairing of customers with products
069	Distinct Subsequences	Determine the number of distinct subsequnces within a string
188	Distinct Triangles	Find the number of distinct triangles formed in a graph
171	DNA Alignment	Find the highest score of DNA sequences alignment
123	Efficient Delivery	Load your tankers with oil
216	Everything or Nothing	Check if a code is correct
085	Find Min	Facebook Hacker Cup 2013 problem
141	Flight 370	Follow the current search results
044	Following Integer	Determine the next number in a sequence
185	Glue Shredded Pieces	Reconstruct the original text from overlapping pieces
060	Grid Walk	The number of grid points that can be accessed
229	Grinch	Help Grinch to find the shortest way
154	IP Package	Calculate IP checksum
088	Juggle Fest	A challenge from Yodle
213	Lakes, Not Cakes	Count all lakes
105	Largest Sub-Matrix	Determine the largest sub-matrix in a matrix
198	Less Money, More Problems	Help citizens by adding new coin denominations
058	Levenshtein Distance	Find out how big the social network of a word is
191	Lights Out	Switch all the lights off with minimum number of moves
006	Longest Common Subsequence	LCS between two strings
182	Longest Path	Find the longest path of unique elements
164	Mars Networks	Find the minimum length of the optical fiber cable which connects probes to a network
036	Message Decoding	Decode an encoded message
079	Minesweeper	Find the mines within a M*N matrix
072	Minimum Path Sum	Calculate the minimum sum of a path through a matrix
114	Package Problem	Put as many things into a package as possible
047	Palindromic Ranges	Find out a range of palindromic numbers
049	Peak Traffic	Finding out which friends you interact with most
126	Play With DNA	Write an algorithm that a finds DNA segment in a given DNA string
086	Poker Hands	Compare two poker hands
007	Prefix Expressions	Evaluating a prefix expression
224	Prisoner or Citizen	In jail or at large?
176	Ray of Light	Trace the path of light distribution
053	Repeated Substring	Find the longest repeated substring in a given text
056	Robot Movements	Number of ways a robot can reach its destination
129	Routing Problem	Find all the shortest paths for the package between two specified hosts
145	Running for President	Build your strategy to win the Presidency of the United States
118	Seat Your Team Members	Place the employees in a new office
120	Skyscrapers	Outline skyscrapers in a city
057	Spiral Printing	Print out a 2D array in spiral order
204	Straight Lines	Print the number of straight lines
038	String List	Create a new string from constituent alphabets
014	String Permutations	Print out all permutations of a string
028	String Searching	Determine if substring match exists
050	String Substitution	Create a new string by replacing substrings within it
059	Telephone Words	Print out the words corresponding to a telephone number
052	Text Dollar	Print out the text dollar amount of a given quantity
110	Text to Number	Convert English text representation of a number to a decimal number
175	The Cubes	Find the length of the shortest way in the multilevel labyrinth
168	The Frequency	Find the signals frequency
157	The Labyrinth	Find the shortest way to exit
219	The Tourist	Find the shortest route between cities
162	Too Unique	Find and mark the biggest submatrices of unique elements
055	Type Ahead	Building a type ahead feature
042	Ugly Numbers	Count the number of expressions that can be created from a number
142	Visit to the Headquarters	Organize the queues
159	Where Is Wi-Fi	Find out in which buildings there are hotspots
207	Which Way Is Faster?	Find the fastest way
065	Word Search	Find if a word exists in a grid

License and Copyright

All original work is released under the MIT license, unless otherwise specified.

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