Define hash table?
Is binary tree a bst?
Differentiate between hashmap and treemap.
Which collection is used for sort?
Define the term “percolate down”?
Is treemap sorted?
Which is better merge sort or quick sort?
applications of stacks and their uses?
Who invented merge sort?
an array of size N in which every number is between 1 and N, determine if there are any duplicates in it. You are allowed to destroy the array if you like. [ I ended up giving about 4 or 5 different solutions for this, each supposedly better than the others ].
Which is faster array or arraylist?
Explain set interface?
Describe the merge sort principle and what will be its time complexity?