Question

"consider a 2-dimensional doubly sorted array a of integers with n-rows and n-columns. I.E. Elements in each row of a are sorted in an increasing order (from left to right), similarly elements in each column are sorted in an increasing order (from top to bottom). You are given such a doubly sorted array a and a number n as input. Goal is to check whether number n is present in the array a or not. Design an efficient algorithm for the problem. Full credit will be given only to an asymptotically faster algorithm than theta(n log n). "

Answer 1

I once made a real-time multi-camera video processing software, doing motion detection and cumulative histographic magic, all on 33MHz processors and 640Mb of RAM. The hard part was making this go fast; copious amounts of hashing, bits-shifting, cheating, swearing and late nights with pizza and ephiphanies for about 4 years. Oh, and I did a version dealing with color as well. Oh, and a module that could see the difference between steam and white smoke in large rooms (like nuclear reactors, as it were). Hah, you just try it! You wouldn't find examples of such in any text-book. :)