2048
You may have seen or played this game on your nearest cell phone: http://en.wikipedia.org/wiki/2048_%28video_game%29 . It is becoming a fever across geeks and addictive-games enthusiastic players across the world. IBM "Ponder This" of this month (April 2014) refers to this game, but instead of a 2D version of it, they came up with a simpler 1D version of it. Link is here: http://domino.research.ibm.com/Comm/wwwr_ponder.nsf/Challenges/April2014.html and here is the problem copied/pasted from their site: " Inspired by the viral 2048 game ( http://en.wikipedia.org/wiki/2048_%28video_game%29 ) game, this month's question is a simpler one-dimensional version of it. Assume that random independent numbers, either 2 or 4 with a 50% chance each, come in from the right side of a bar with N slots. The numbers are always squeezed to the left and every time two adjacent numbers are the same - they are replaced by their sum. The game ends when all the N slots are occupied