Compounding the cost, most mapping software is processor-intense.
Good candidates can arrive at the binary search tree as the right path in a few minutes, and then take 10-15 minutes working through the rest of the problem and the other roadblocks I toss out. But occasionally I get a candidate who 'intuitively understands' trees and can visualize the problem I'm presenting.
Realize you won't master data structures until you are working on a real-world problem and discover that a hash is the solution to your performance woes.
The key to a solid foundation in data structures and algorithms is not an exhaustive survey of every conceivable data structure and its subforms, with memorization of each's Big-O value and amortized cost.
