Collection of quick problems:

1) Reversing a string.
2) Given N nodes, reverse them.
3) Given N nodes, find the middle one.
4) Dynamic programming approach to calculating the nth fibonacci number (with memoization/caching).
5) Finding the missing number in an array of integers from 1..N.
6) Given an array of ints, find all pairs of ints that sum to number N.
7) Given a sorted array of ints, insert a new element into it.
8) Insert/Delete into/from binary tree. (i.e. BST impl).
9) ...