Chapter 1 — Algorithms complexity
Chapter 3 — Common design paradigms
Chapter 5 — Combinatorial search and heuristics methods
Chapter 6 — In progress...
List of algorithm general topics
List of algorithms — it's really huge. It's just as an example. You shouldn't know them all.
HackerRank — the most popular site
HackerEarth — good explanations
CodeWars — I just like it :)