In contrast, a data structure is a concrete implementation of one or more ADTs, similar to how Java classes implement interfaces. Examples of ADTs include Employee, Vehicle, Array, and List.

When you create a HashMap, what the Java virtual machine does is it creates a single-dimensional array to hold all of your data, to hold everything that you want to put into your HashMap. Now, there's ...

Recall that O(1) is pronounced “Big Oh of 1.” (See Part 1 for a reminder of how time and space complexity measurements are used to evaluate data structures.) Inserting nodes into a singly ...