Algorithms (also known as Computer Programming 101)

1. Nitin Reddy Katkam
n4express.com
nitinkatkam.com
knreddy.com

2.  A sequence of instructions
 A precise step-by-step procedure
 The first step to writing the program
(i.e. the idea in your head)

3.  Often, algorithms should not just work, but
should also run efficiently
 Time taken for execution
 Memory used for execution
 Big-O Notation
 A measure of increase in computation for an
increase in input
 Different from the Little-O Notation

4.  Example: Search an array of ‘n’ elements for a
value
 Compare each element
 O(N) algorithm
 Example: Set the first element of an array of
‘n’ elements to zero
 Set array[0] = 0 //sets the 1st element to 0
 O(1) algorithm

5.  Bubble Sort: O(n2)
 Selection Sort: O(n2)
 Merge Sort:
 Linear Search: O(n)
 Binary Search: O(log n)