Algorithms Hashed Array Tree: Efficient representation of Array Hashed Array Tree is an improvement over Dynamic Arrays where there can be a large amount of unused allocated memory at a time. This can be visualized as a 2 dimensional array and has been developed by Robert Sedgewick, Erik Demaine and others.
Software Engineering Defaultdict (Default Dictionary) in Python A default dictionary is a dictionary that automatically assigns default values to keys, if queried keys are not present. The default dictionary is Python's intelligent hash table.
