The good thing about Algorithm Design & Analysis as a topic is that there is no lack of great resources to learn from! And even better, a large portion of them are freely available online (in forms of lecture notes, or entire books, video lectures, programming challenges with online judging, etc).

In addition to what others have mentioned, here are some example resources you might prefer for a beginner-intermediate level intro:

1. (free online) Algorithms by Dasgupta, Papadimitriou, and Vazirani http://algorithmics.lsi.upc.edu/docs/Dasgupta-Papadimitriou-...

2. (free online) Algorithms by Jeff Erickson https://jeffe.cs.illinois.edu/teaching/algorithms/

3. Algorithm design by Kleinberg & Tardos https://www.amazon.com/Algorithm-Design-Jon-Kleinberg/dp/032...

4. Another one specifically for more applied view (esp., how they are used in programming contests such as ICPC) is Skiena & Revilla's "Programming Challenges" book (https://www.amazon.com/Programming-Challenges-Contest-Traini...). Note that this is different than Skiena's other popular book (Algorithm Design manual) which is also pretty good and has a "war story" based perspective to design of algorithms.

5. There are also several resources where lecture notes from university Algorithm & DS courses are very useful. Here is an example from my previous Professor, David Kempe: http://david-kempe.com/teaching/DataStructures.pdf

6. Several programming competition specific tutorials can be found on Topcoder: https://www.topcoder.com/thrive/tracks?track=Competitive%20P... (individual SRM archives are also good place to try problems first hand and then learn from other's approach). In general, if you search for ACM-ICPC resources, you will find a lot more targeted information/problems which will apply not only for leetcode, but also for detailed understanding of the theory too.

i prefer tardos/kleinberg{http://www.amazon.com/Algorithm-Design-Jon-Kleinberg/dp/0321...} for algorithms, at least for self study. The book has solutions, doesnt leave any proofs incomplete and has a little bit more focus on real world examples. its also half as long, but still covers 3/4 of the material.

Both solid choices. Having used CLRS (the Intro the Algorithms book), I would say it's a fantastic reference, but I found some of the presentation rather terse. It is nothing that a motivated reader can't power through, but some people have also suggested Kleinberg and Tardos's algorithms book for better pedagogical development http://www.amazon.com/Algorithm-Design-Jon-Kleinberg/dp/0321...

What's wrong with less cryptic books like these?

http://www.amazon.com/Algorithm-Design-Jon-Kleinberg/dp/0321...

http://www.amazon.com/Introduction-Algorithms-Third-Thomas-C...

I'd suggest Algorithm Design by Kleinberg and Tardos: http://www.amazon.com/Algorithm-Design-Jon-Kleinberg/dp/0321... , it's more readable than either CLRS or Dasgupta/Papadimitriou/Vazirani.

Ah, apologies:

  Algorithm Design   by Jon Kleinberg & Éva Tardos   ISBN: 978-0-321-29535-8 

Or an Amazon link: http://www.amazon.com/Algorithm-Design-Jon-Kleinberg/dp/0321...