How would you list words that are anagrams of each other?
I was asked this question when I applied for my current job.
orchestra can be rearrang
Good thing we all live in the C# reality of in-place sorting of short words on quad core machines with oozles of memory. :-)
However, if you happen to be memory constrained and can't touch the original data and you know that those words contain characters from the lower half of the ASCII table, you could go for a different algorithm that counts the occurrence of each letter in each word instead of sorting.
You could also opt for that algorithm if you want to do it in O(N) and don't care about the memory usage (a counter for each Unicode char can be quite expensive).