Best place to learn Data Structure and Algorithms Online

In this post you will know the best place to learn data structures and algorithms through online. Before learning algorithms/ds, learn a programming language first.  The following are the 3 best places to learn ds and algorithms. They are

1. https://www.udemy.com/introduction-to-algorithms-and-data-structures-in-c/

2. Abdul Bari:

3. CS Dojo: