The other day, I was curious about this thing and couldn't find a similar older question so.. decided to post this.
I do not know much beyond the basic algorithms 101 knowledge. Probably the only stuff I know outside of that is Heavy-Light decomposition and Persistent Segment tree. My favorite problems are those which are hard but solvable with just the basic 101 knowledge.
I am curious if there are grandmasters who have the same level of knowledge that I do and not more. While knowing more algorithms/data structures may surely help, it's interesting for me to see high rated performers who got there with just the basic algorithms 101 knowledge.