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good practice for generics. this is a generic static method, it takes an array of any type of item.
sortArray<T>(T[] array){...} I think.

the method has to implement Comparable or something, comparison/equality of generic items must be defined.

Learn how great trace is for understanding what you built.

Try a recursive method that reverses a pointer, then calls itself.

Emre had this in an interview.

An array of objects contain duplicate items (object references that are pointing to the same object).

Can you quickly O(N) discover and remove the duplicates?

1. a == b is true if the reference is the same (ie the same object)
2. Testing each element against every other is N^2.
3. Emre's interlocutor taught him to add a property to each object...?

Original Problem Spec
Using whatever resources you want, please write a JavaScript function that takes an array of objects and returns a unique-ified version of the same array.

To be clear, there could be objects that are copies or duplicates of other objects, but the goal is to just remove the duplicates, not the copies. Duplicates means references to the same object in memory. Copies means different objects in memory with the same properties. The level of nesting in the object should not matter.

There are multiple ways to solve this, but the goal is to solve it with an algorithm that is as fast as possible.

How many palindrome numbers are there from 0 to 2000. Can you do that in your head?

http://stackoverflow.com/questions/6401289/how-to-find-out-all-palindromic-numbers

start with integers.
you can build it to include generics, which then have a comparable interface.

small change, to accept list items of any type

How Java handles references to object is hugely important. Work through the examples until you understand the implications and the bugs that can come from this feature.

Some links
Method arguments are passed by value (which are references) java world explanation
Stackoverflow

Do a tutorial on Collections, and some exercises.

take a linked list of arbitrary length, reverse it's order.
not by duplicating, just manipulating node pointers with a few variables maybe.
for starters assume simple data type, finish with Generic