Introduction Clarence is a data entry clerk who works at an internet service provider. His job is to manually enter the IP addresses of all of the ISP's customers into the database. He does this using a keypad which has the following layout: 123 456 789 .0 The distance between the centre of ho...

Pandora's Pancakes popularity-contest underhanded Introduction A long time ago, when this old world was still in its infancy, there existed a child named Pandora. She visited another child named Epimetheus. The first thing she saw when she entered the cottage in which Epimetheus dwelt was a la...

Question about mapping a river code-golf graphs Introduction A certain area has a system of rivers running through it. A map must be made of the river. However, the area is covered with many dangerous man-eating plants, so thus far, any cartographer who has tried to get close was simply eaten ...

Given the size of the chess board and initial position of the knight, what is the probability that after k moves the knight will be inside the chess board. Note:- 1) The knight makes its all 8 possible moves with equal probability. 2) Once the knight is outside the chess board it cannot come b...

Let n > 0. Let X = [1..n] and Y = [n+1 .. 2n]. Define a(n) as the number of permutations p of Y such that every element of X + p(Y) is prime. For example: n = 2 X = [1,2] Y = [3,4] p0(Y) = [3,4] => X + p0(Y) = [4,6] => No p1(Y) = [4,3] => X + p1(Y) = [5,5] => Yes a(2) = 1 In as few bytes as ...

Is this a red-black tree? A red-black tree is a binary search tree where each node has an additional 'colour' property, which can be black or red. The root and leaf nodes must be black, each red node must have black children, and the path from any node to any child leaves must have the same numb...

Question about a race car track! (title tbd) Background My niece wants to make a race car track. She has wooden parts that fit together to form the track. Each part is square shaped and contains a different shape. I'll use the pipe drawing characters to illustrate: │: the road that goes verti...

This is a byte sized challenge where you have to convert an input temperature in one of the three units (Celsius, Kelvin and Fahrenheit) to the other two. Input You would be provided with a temperature as a number followed by a unit (separated by space). The temperature can be an integer or a f...

Given a table of size n * m, with each cell having a color value from the set {r, g, b}, find the area of the largest triangle that has one side parallel with the y – axis (vertical) and has no two vertices that have the same color value. Input : First line contains the size of the matrix i.e. ...

...at least for some definition of "self-modification". The Task In this challenge, your task is to write three strings A, B and C that satisfy the following properties. The string B has length at least 1. For every n ≥ 0, the string ABnC is a valid program (meaning full runnable program or f...

Context: Are Stack Snippets a good enough reason to increase the 30k post limit? http://chat.stackexchange.com/transcript/message/21826346#21826346 Are Stack Snippets a good enough reason to increase the 30k post limit?

Background: Every war eventually comes to an end, but the end is never absolute. The Stone Maze Chess scenario takes place after a game of chess is finished. The enemy King is dead and the pieces is lost in vacuity almost out of faith, multiplying. The winning side has moved on except for the He...