Searching

* Sequential Search O(N)

* Binary Search O(logN)

* Hashing O(1)

* Binary Search Tree O(logN)

* Key Index to Array O(1)
Note its different space requirement from that of hashing

* Examples
- Find the missing/duplicate element in one unsorted array
Binary search for large array. In some cases, it could be solved by calculating the difference between the sum of the array and the sum of the range of number.
- Find all sets of angrams in one dictionary
Set a key for each word, then sort by the key to group them.
- Find the angrams of one word in one dictionary
After finish Q2, use binary search to do it.
- Find the Kth largest number in one non-repeated array
Order statistics
- Find the median of two sorted arrays
- Find one number which duplicates more than half size of one array
- Bitmap sort actually uses key index