Uniform Iterative&Recursive solutions for tree traversal in in/pre/post order

https://github.com/tianlixu/leetcode/blob/master/94-binary-tree-inorder-traversal.cpp
https://github.com/tianlixu/leetcode/blob/master/145-binary-tree-preorder-traversal.cpp
https://github.com/tianlixu/leetcode/blob/master/146-binary-tree-postorder-traversal.cpp

Binary Tree Tranversal

Inorder Traversal : LVR
Preorder Traversal: VLR
Postorder Traversal: LRV

   depends on the position of V.
Level Traversal: BFS

Bubble Sort

BubbleSort.pdf

Find the Median - To be continued

The median is the "middle number" in a sorted list of numbers. If it's odd, then it is the middle value. If it's even, it's the average of the two middle values.

/* Problem:
 * How to find the median of a sorted array?
 * How to find the median of an unsorted array?
 * How to find the median of an unsorted array without sorting?
 *
 * How to find the median of two sorted array? - from LeetCode
 * How to find the median of given N sorted arrays?
 */




Reference:
    http://en.wikipedia.org/wiki/Median_of_medians