Have you actually ever competed in online competitions like Topcoder or algorithm competitions like ACM ICPC? For solving these kind of problems knowing a bunc

Have you actually ever competed in online competitions like Topcoder or algorithm competitions like ACM ICPC? For solving these kind of problems knowing a bunch of known algorithms won't take you too far. They will only be useful in the beginner stages, but as you progress you need to invent new algorithms, make modifications to the existing algorithms (so they test that you really understand the idea behind them), combine different algorithm design techniques, etcetera. They are often a good proxy to test how creative in problem solving you can be, not just mere rote memorization of algorithms and how good are you at remembering known algorithms.