Leetcode is a great website for learning. This has helped me find me next opportunity.
However, my pet peeve had been that I cannot add my own tests cases easily in leetcode. I found it useful to understand the question by adding my own tests cases and then debugging locally when I got struck.

To solve it, me and my friend @pvovveti created the questions of leetcode locally and worked through them. This immensily helped me in my interviewing. To help the community we created a public version of it and have setup the project to run in both Java and Scala (Kotlin coming up soon).

So, if you are like me who wants to use intellij/eclipse to code, here is your option.

https://github.com/superaghu/LeetCodeLocally

Comments/Feedback/Contribution welcome.