You are given the data set of all Google crawled URLs on the Internet -- that's a very large set. Write an algorithm to find the median URL length.

Seven people are blindfolded and given unique colored hats at a roundtable. How should they cooperate for at least one to guess her own color?

I take n consecutive integers, toss one of them out and mix up the remaining n-1 integers as completely unsorted. Find the missing integer.

How many binary tree topologies are possible given n nodes?

You are given n, a positive integer. Return true if n is a prime number, and false if it's not.

An employer hires you to work for 7 days and has a gold bar with 7 segments to pay you with. How do you get them to not break it to pieces?

You are given eight balls that look exactly the same, and a balance to weigh them against each other. Find the odd ball by weighing only twice?