You can learn and can explore beginner type coding platforms such as Hackerrank to explore more about online coding and Coding Platforms such as Leetcode and GeeksforGeeks are recommended The Resources given are some that can be used to prepare, If you feel that U have some other resource and maybe you are able to understand from some other resource, U can surely go for the same.

Also, Refer all the popular sheets and some guided paths with questions from CodeStudio

Topic	Resources
Language - C++/Java	1. C++ 2. Libraries : Video1, Video2, Video3, Video4 3. Java 4. Libraries
Time and Space Complexity	Playlist
Arrays, Searching, Sorting and Matrix	Practice Good Quality Questions on Arrays and Matrix as you just need to know what are arrays, rest is just Practice and then you can know other different Algorithms For Searching Playlist, Playlist, Playlist For Sorting Playlist, Playlist Sliding Window Playlist
Strings	Video1 and again some good Quality questions that will help understanding the topic in depth.
Hashing	Playlist
Recursion and Backtracking	Playlist1, Playlist2
Linked List - All types(LL, CLL, DLL)	Playlist and some Questions from Leetcode or GeeksforGeeks
Stacks, Queues and Dequeues	Stacks - Playlist and for Queues and Dequeues, just go through some GeeksforGeeks articles or any Youtube Vido, Probably this and understand what is a Queue and Dequeue and then solve some Questions on these topics
Trees and Binary Search Trees	Playlist
Heaps	Playlist
Greedy	Read about Greedy Algorithms or any Youtube Video and Practice some Questions on the same, Video Video
Graphs	Playlist
Dynamic Programming	Playlist, Playlist
Mathematics and Bit Manipulation	Playlist