1. Topcoder tutorials- Data Science Tutorial
2. Very good for starters- Page on iarcs.org.in
3. CS 97SI: Introduction to Competitive Programming Contests
4. List of some reknowned algorithms- Data Structures and Algorithms
5. Begin with DP- Introduction to Dynamic Programming
6. BigO CheatSheet- Big-O Algorithm Complexity Cheat Sheet
7. Good Fenwick tree tutorial- Fenwick trees demystified
8. A Very good blog entry on DS- Algorithm Gym :: Data structures – Codeforces
9. Kind of a Bible- Basic Algorithms & Data-Structures
10. Another Course to refer- T-414-ÁFLV: A Competitive Programming Course