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Skip this and go directly to challenges!

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**.

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 | Foundation | Array | Sum all elements of an array. | 3.9 | 298 | root | 2015-11-02 | |

## Capitalize 2nd Word | Foundation | Array, String | Capitalize the second word of a string. | 4.1 | 263 | root | 2015-11-02 | |

## Ends | Foundation | Array | Return array that contains only the input array start and end values. | 4.3 | 220 | root | 2015-11-17 | |

## Multiple of 5 or 7 | Foundation | Modulus | Determine if a number is a multiple of 5 or 7. | 4.5 | 205 | root | 2015-11-16 | |

## Pythagorean Theorem | Foundation | Math, Object | Use Math object to compute Pythagorean theorem. | 4.2 | 163 | root | 2015-11-02 | |

## Reverse Sort | Foundation | Array, Sort | Use array sort method to sort array in descending order. | 4.3 | 162 | root | 2015-11-02 | |

## Search Object | Foundation | Search, Object | Determine if any properties of an object contain a specific value. | 4.4 | 175 | root | 2015-11-06 | |

## 13 + 1 | Easy | Modulus | Determine if a number is a multiple of 13 or 1 greater then a multiple of 13. | 4.1 | 144 | root | 2015-11-17 | |

## Bounding Box | Easy | Geometry | Compute the smallest bounding box that contains all points. | 4.4 | 132 | root | 2015-10-29 | |

## Combine Overlaps | Easy | Array | Combine overlapping ranges into a single range. | 5 | 75 | root | 2015-11-07 | |

## Contains Duplicate | Easy | String | Determine if a string contains any duplicate letters. | 4.1 | 96 | root | 2015-10-28 | |

## Create Biggest Number | Easy | Array | Combine Array of numbers so resulting number is as large as possible. | 4.5 | 33 | root | 2015-11-06 | |

## Don't Tell Fibs | Easy | Puzzle | This is a puzzle challenge. | 4 | 27 | root | 2015-11-02 | |

## Encode Repeats | Easy | String | Replace repeated letters in a string with the letter count. | 4.7 | 21 | root | 2015-10-29 | |

## Even Spacing | Easy | Array, Math | Determine if all values in a set of integers are evenly spaced. | 4.3 | 30 | root | 2015-11-19 | |

## Find Common Array Elements | Easy | Search, Array | Given two arrays, find all integers that appear in both arrays. | 4.4 | 31 | root | 2015-10-25 | |

## Greatest Common Divisor | Easy | Math, Iteration | Find the greatest common divisor of two integers. | 5 | 26 | lwear | 2015-10-24 | |

## Grocery Stamps | Easy | Math | Determine how many stamps a customer should get using custom rounding rule. | 5 | 26 | root | 2015-11-17 | |

## Intersecting Lines | Easy | Geometry | Determine if two lines intersect. | 3.5 | 11 | root | 2015-11-06 | |

## Overlapping Circles | Easy | Geometry | Determine if two circles overlap or touch. | 5 | 14 | root | 2015-10-29 | |

## Palindrome | Easy | String | Determine if a string is a palindrome, ignoring white space, punctuation, and case. | 1 | 10 | root | 2015-10-28 | |

## Prime? | Easy | Math, Modulus | Determine if a positive integer is prime. | 4.4 | 34 | root | 2015-11-20 | |

## Reorder CSV Column | Easy | String, Array | Reorder columns for each line of a comma separated value (CSV) string. | 5 | 20 | root | 2015-11-06 | |

## Rotate Array | Easy | Array | Rotate array n elements to the right. | 5 | 16 | root | 2015-10-20 | |

## Shuffle Arrays | Easy | Array | Shuffle two arrays into one. | 5 | 15 | root | 2015-10-28 | |

## Simplified Pig Latin | Easy | String | Convert string to Pig Latin | 5 | 17 | root | 2015-10-29 | |

## Substitution Cipher I | Easy | String, Cryptography | Encode string using a simple substitution cipher. | - | 9 | root | 2015-11-04 | |

## Sum Distinct | Easy | Array | Sum all distinct numbers in an array. | 5 | 13 | root | 2015-11-19 | |

## Unwind | Easy | Array | Unwind matrix of letters in a clockwise direction. | 5 | 22 | root | 2015-11-06 | |

## Ackermann Function | Medium | Recursion | Implement Two-Argument Ackermann Function | 2.5 | 26 | root | 2015-11-08 | |

## Braces/Brackets/Parentheses | Medium | String, Stack | Determine if string contains matching and correctly nested Braces/Brackets/Parentheses | 5 | 18 | root | 2015-10-29 | |

## Dice >= Odds | Medium | Probability | Determine odds of rolled dice being greater than or equal to number. | 4 | 17 | root | 2015-11-03 | |

## Formulas of 1 through 6 | Medium | Search, Math | Given integer, determine formula using numbers 1 through 6, +, -. | - | 4 | root | 2015-11-04 | |

## Isomorphic Strings | Medium | String | Determine if two strings are isomorphic. | 4.7 | 15 | root | 2015-11-02 | |

## Largest Duplicate Count | Medium | Map | Count the letter with the most duplicates. | 4 | 24 | root | 2015-10-28 | |

## Line? | Medium | Geometry | Determine if 3 points form a strait line. | 4 | 28 | root | 2016-07-26 | |

## Mean == Mode | Medium | Math, Map | Determine if an array of integers has the same Mean and Mode. | - | 15 | root | 2016-04-27 | |

## Reverse Polish Notation | Medium | Stack | Evaluate formula given in reverse polish notation. | 5 | 6 | root | 2015-10-19 | |

## Rotate Matrix | Medium | Array, Matrix | Rotate a square matrix (2D array) 90 degrees clockwise. | - | 3 | root | 2015-11-18 | |

## Search Sorted Matrix | Medium | Search, Matrix | Search a sorted 2D matrix. | - | 41 | root | 2015-11-06 | |

## Substitution Cipher II | Medium | String, Cryptography | Encode string using a substitution cipher. | - | 4 | root | 2015-11-04 | |

## Substitution Cipher III | Medium | String, Cryptography | Encode string using a complex substitution cipher. | 4 | 5 | root | 2015-11-04 | |

## Sudan Function | Medium | Recursion | Implement Sudan Function | - | 7 | root | 2015-11-08 | |

## Sumable | Medium | Array, Recursion | Given an array of integers, determine if a subset of the array add to a target number. | - | 4 | root | 2015-11-18 | |

## Theatre Line Change | Medium | Map | Can the theatre box office make change for everyone in the line. | 4.5 | 6 | root | 2015-11-18 | |

## Tiles | Medium | Math, Modulus | Determine if you can combine small and big tiles to create a specific length. | 4.5 | 19 | root | 2015-11-18 |

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