Want to participate in coding wars? Compete with other coders worldwide by participating in the contests. You also earn points for your achievements.
Geek for Geeks
This website is the best place to practice programming problems, review company interview questions, and improve your coding skills
HackerRank
This resource provides developers with competitive programming challenges to improve their skills in multiple languages. It also allows tech recruiters to assess developers on their problem-solving skills.
LeetCode
This site offers competitive coding challenges and interview preparation resources for software engineers and developers.
SPOJ
SPOJ is an online judge system with over 315,000 registered users and over 20,000 problems.