Good website/resource for competitive programming.

general
1

Which website/resource are good for competitive programming ?

2

use topcoder tutorials and Introduction to Algo by Thomas Cormen … really useful

3

Sites to practice solving problems:

TopCoder

Codechef

Codeforces

SPOJ

Hackerrank

Hackerearth

UVA OJ

Books:

CLRS (Introduction to Algorithms)

U. Vazirani (Algorithms)

Programming Challenges (Skiena)