After a while decided to post some more problem solutions. The first problem this year is about looking for a node in a DOM tree: given two identical DOM tree structures, A and B, and a node from A, find the corresponding node in B.
How to get a powerset of a set? With ease.
Decided to post my implementation of solving Towers of Hanoi problem
Found a problem about grouping together rotationally equivalent words from a given array of words