EppsNet Archive: Mathematics

Competitive Programming: POJ 1426 – Find The Multiple

Description Given a positive integer n, write a program to find out a nonzero multiple m of n whose decimal representation contains only the digits 0 and 1. You may assume that n is not greater than 200 and there is a corresponding m containing no more than 100 decimal digits. Input The input file may contain multiple test cases.… Read more →

Competitive Programming: POJ 2084 – Game of Connections

Description This is a small but ancient game. You are supposed to write down the numbers 1, 2, 3, . . . , 2n – 1, 2n consecutively in clockwise order on the ground to form a circle, and then, to draw some straight line segments to connect them into number pairs. Every number must be connected to exactly one… Read more →

Competitive Programming: POJ 1654 – Area

Description Consider an infinite full binary search tree (see the figure below), the numbers in the nodes are 1, 2, 3, …. In a subtree whose root node is X, we can get the minimum number in this subtree by repeating going down the left node until the last level, and we can also find the maximum number by going… Read more →

Competitive Programming: POJ 2242 — The Circumference of the Circle

Description To calculate the circumference of a circle seems to be an easy task – provided you know its diameter. But what if you don’t? You are given the cartesian coordinates of three non-collinear points in the plane. Your job is to calculate the circumference of the unique circle that intersects all three points. Input The input will contain one… Read more →

Are You Smarter Than a Common Core Algebra Student?

You can test your Common Core algebra skills against a 5-question sample test courtesy of the the New York Times. For all the controversy about Common Core, the questions seem pretty basic even for a person with an aging brain (I frigging CRUSHED it with a perfect 5 out of 5), the one exception being a graphing problem that should… Read more →

A Mega Millions Lottery Ticket is a Good Investment

Mega Millions uses 75 numbers for the first five selections and 15 numbers for the Mega ball. The number of unique combinations of five numbers selected from a pool of 75 is Multiply that times 15 possibilities for the Mega ball and the odds of winning come out to 1 in 258,890,850. BUT THE CURRENT MEGA MILLIONS JACKPOT IS OVER… Read more →

The Epps Ratio

There should be some way to measure a person’s need to be heard against the value of what they have to say. This measure should be calculated automatically and be available online, like a Klout score. If anyone figures out a way to do this, please call it the Epps Ratio, because it was my idea. Value should be the… Read more →