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Skip this and go directly to challenges!

/* It's OK, everyone was a n00b once. */


Everyone should start by completing the n00b challenges which teach you how to use IOKungFoo. An experienced coder will be able to complete them all in only a few minutes. You can find this page again by clicking on Open->n00b.



/* What's Next? */


Once the n00b challenges are complete you can pick any challenge under Open->To Do (see above). Beginner coders should start with the Foundation challenges which review basic skills. Experienced coders can jump right into the Easy or Medium challenges.

Title Difficulty Tags Summary Rating Solved Author Created

Array Summation

FoundationArraySum all elements of an array.3.9337root2015-11-02

Capitalize 2nd Word

FoundationArray, StringCapitalize the second word of a string.4.1287root2015-11-02


FoundationArrayReturn array that contains only the input array start and end values.4.2247root2015-11-17

Multiple of 5 or 7

FoundationModulusDetermine if a number is a multiple of 5 or 7.4.4230root2015-11-16

Pythagorean Theorem

FoundationMath, ObjectUse Math object to compute Pythagorean theorem.4.2182root2015-11-02

Reverse Sort

FoundationArray, SortUse array sort method to sort array in descending order.4.3178root2015-11-02

Search Object

FoundationSearch, ObjectDetermine if any properties of an object contain a specific value.4.2201root2015-11-06

13 + 1

EasyModulusDetermine if a number is a multiple of 13 or 1 greater then a multiple of 13.4.1163root2015-11-17

Bounding Box

EasyGeometryCompute the smallest bounding box that contains all points.4.5139root2015-10-29

Combine Overlaps

EasyArrayCombine overlapping ranges into a single range.576root2015-11-07

Contains Duplicate

EasyStringDetermine if a string contains any duplicate letters.4.1115root2015-10-28

Create Biggest Number

EasyArrayCombine Array of numbers so resulting number is as large as possible.4.741root2015-11-06

Don't Tell Fibs

EasyPuzzleThis is a puzzle challenge.429root2015-11-02

Encode Repeats

EasyStringReplace repeated letters in a string with the letter count.4.722root2015-10-29

Even Spacing

EasyArray, MathDetermine if all values in a set of integers are evenly spaced.4.332root2015-11-19

Find Common Array Elements

EasySearch, ArrayGiven two arrays, find all integers that appear in both arrays.4.437root2015-10-25

Greatest Common Divisor

EasyMath, IterationFind the greatest common divisor of two integers.527lwear2015-10-24

Grocery Stamps

EasyMathDetermine how many stamps a customer should get using custom rounding rule.529root2015-11-17

Intersecting Lines

EasyGeometryDetermine if two lines intersect.3.511root2015-11-06

Overlapping Circles

EasyGeometryDetermine if two circles overlap or touch.514root2015-10-29


EasyStringDetermine if a string is a palindrome, ignoring white space, punctuation, and case.110root2015-10-28


EasyMath, ModulusDetermine if a positive integer is prime.4.436root2015-11-20

Reorder CSV Column

EasyString, ArrayReorder columns for each line of a comma separated value (CSV) string.520root2015-11-06

Rotate Array

EasyArrayRotate array n elements to the right.516root2015-10-20

Shuffle Arrays

EasyArrayShuffle two arrays into one.515root2015-10-28

Simplified Pig Latin

EasyStringConvert string to Pig Latin517root2015-10-29

Substitution Cipher I

EasyString, CryptographyEncode string using a simple substitution cipher.-9root2015-11-04

Sum Distinct

EasyArraySum all distinct numbers in an array.513root2015-11-19


EasyArrayUnwind matrix of letters in a clockwise direction.522root2015-11-06

Ackermann Function

MediumRecursionImplement Two-Argument Ackermann Function2.526root2015-11-08


MediumString, StackDetermine if string contains matching and correctly nested Braces/Brackets/Parentheses4.520root2015-10-29

Dice >= Odds

MediumProbabilityDetermine odds of rolled dice being greater than or equal to number.417root2015-11-03

Formulas of 1 through 6

MediumSearch, MathGiven integer, determine formula using numbers 1 through 6, +, -.-4root2015-11-04

Isomorphic Strings

MediumStringDetermine if two strings are isomorphic.4.715root2015-11-02

Largest Duplicate Count

MediumMapCount the letter with the most duplicates.424root2015-10-28


MediumGeometryDetermine if 3 points form a strait line.428root2016-07-26

Mean == Mode

MediumMath, MapDetermine if an array of integers has the same Mean and Mode.516root2016-04-27

Reverse Polish Notation

MediumStackEvaluate formula given in reverse polish notation.56root2015-10-19

Rotate Matrix

MediumArray, MatrixRotate a square matrix (2D array) 90 degrees clockwise.-3root2015-11-18

Search Sorted Matrix

MediumSearch, MatrixSearch a sorted 2D matrix.-42root2015-11-06

Substitution Cipher II

MediumString, CryptographyEncode string using a substitution cipher.-4root2015-11-04

Substitution Cipher III

MediumString, CryptographyEncode string using a complex substitution cipher.45root2015-11-04

Sudan Function

MediumRecursionImplement Sudan Function-7root2015-11-08


MediumArray, RecursionGiven an array of integers, determine if a subset of the array add to a target number.-4root2015-11-18

Theatre Line Change

MediumMapCan the theatre box office make change for everyone in the line.4.56root2015-11-18


MediumMath, ModulusDetermine if you can combine small and big tiles to create a specific length.4.519root2015-11-18

New challenges are being added all the time. Check back often.