<p>MegaFirm Inc. has created a set of patterns to aid its telephone help-desk operators in responding to customers. A pattern is a phrase consisting of words and placeholders. A word is simply a string of letters. A placeholder is a word enclosed in angl…

<p>A permutation of <em>n</em> is a bijective function of the initial <em>n</em> natural numbers: 0, 1, ... <em>n</em>-1. A permutation <em>p</em> is called antiarithmetic if there is no subsequence of it f…

<p>Consider a grid in which north-south streets, separated by gaps of 10 miles each, are elevated above east-west streets laid out in a similar fashion (see illustration for the case of a 6 by 6 grid). All streets are two-way. Entrance and exit ramps con…

<img align="right" src="/admin/../upload/pimg1176_1.jpg" alt="" /></p><p>In strong winds, sailboats tend to heel leeward (tilt away from the wind) like the one in the picture. Heeling is undesirable for at least two reasons. First, the effect…

<p><img align="left" alt="" src="/admin/../upload/pimg1164_1.gif" /></p> <p>You are attempting to learn to play a simple arcade dancing game. The game has 4 arrows set into a pad: Up, Left, Down, Right. While a song plays, you watch arr…

<p>Now that you're back to school for another term, you need to remember how to work the combination lock on your locker. A common design is that of the Master Brand, shown at right. The lock has a dial with 40 calibration marks numbered 0 to 39. A combi…