algorithms
Competitive Programming Challenge Solutions
open-to-updates
More than 80 solutions (and growing every day) to problems of the popular platforms:
Mostly solutions written in modern programming languages such as Swift and Kotlin.
I recommend using these solutions as a reference after solving them on the platforms. It's good to see alternative solutions or in other languages that you use.
Creating a habit to solve a daily problem is very good to improve the programming logic day by day. Just like going to the gym is good for the body. For example LeetCode has a daily challenge and they have rewards.
You can follow the progress in this list.