There are plenty of sites that help you improve your coding skills and prepare for technical interviews like:
HackerRank
CheckiO
CodeAbbey
CodeWars
CodinGame
LeetCode
etc.
Do you use any of these? What is in your opinion the best one? I’ve using CodeWars for a while and i’ve been enjoying it but i’d like to know if there’s something better out there If yours isn’t in this quick made list or you have any other opinion about these sites, please feel free to share it.
Hackerrank is great, but if you’re willing to branch out, CodeChef, TopCoder and Codeforces hold better contests with better problems. Those would require learning C++, C, Java or (on a few) Python. However, coding skills translate to any language, so I would recommend giving these a go.