Best resources to boost your programming skills through practice
Resource
Codewars.com - choose your level, choose programming languages you wish to train on and boost your skills from any level. Higher programming skills - higher difficulty of tasks.

Leetcode.com - well-known website to prepare for technical interviews and solve algorithmic tasks on different level of coding experience

Hackerrank.com - online competitions between programmers. A mention of a high place in such competitions can be a useful point on a CV, and the most distinguished participants are often invited to internships.

Topcoder.com - biggest resource for sport programmers

Edabit.com - Learn to code with 10,000+ interactive challenges. The fastest and easiest way to learn programming.

Codingame.com - code on different programming languages and change the scenario of the game

Enjoy!