Probably the two most common self balancing tree algorithms are Red-Black trees and AVL trees. To balance the tree after an insertion/update both algorithms use the notion of rotations where the nodes of the tree are rotated to perform the re-balancing. While in both algorithms the insert/delete operations are O(log n), in the case of … Read more
Off the top of my head: Array* – represents an old-school memory array – kind of like a alias for a normal type[] array. Can enumerate. Can’t grow automatically. I would assume very fast insert and retrival speed. ArrayList – automatically growing array. Adds more overhead. Can enum., probably slower than a normal array but … Read more
What is the best way to implement nested dictionaries in Python? This is a bad idea, don’t do it. Instead, use a regular dictionary and use dict.setdefault where apropos, so when keys are missing under normal usage you get the expected KeyError. If you insist on getting this behavior, here’s how to shoot yourself in … Read more
You might like IntervalHeap from the C5 Generic Collection Library. To quote the user guide Class IntervalHeap<T> implements interface IPriorityQueue<T> using an interval heap stored as an array of pairs. The FindMin and FindMax operations, and the indexer’s get-accessor, take time O(1). The DeleteMin, DeleteMax, Add and Update operations, and the indexer’s set-accessor, take time … Read more
For one thing, it’s more sensible in terms of inheritance. The fact that Stack extends Vector is really strange, in my view. Early in Java, inheritance was overused IMO – Properties being another example. For me, the crucial word in the docs you quoted is consistent. Deque exposes a set of operations which is all … Read more
Because sets have no ordering. Some implementations do (particularly those implementing the java.util.SortedSet interface), but that is not a general property of sets. If you’re trying to use sets this way, you should consider using a list instead.
It depends on what you are intending to do with it. Sets are significantly faster when it comes to determining if an object is present in the set (as in x in s), but its elements are not ordered so you cannot access items by index as you would in a list. Sets are also … Read more
Two terms for the same thing: “Map” is used by Java, C++ “Dictionary” is used by .Net, Python “Associative array” is used by PHP “Map” is the correct mathematical term, but it is avoided because it has a separate meaning in functional programming. Some languages use still other terms (“Object” in Javascript, “Hash” in Ruby, … Read more
Skip lists are more amenable to concurrent access/modification. Herb Sutter wrote an article about data structure in concurrent environments. It has more indepth information. The most frequently used implementation of a binary search tree is a red-black tree. The concurrent problems come in when the tree is modified it often needs to rebalance. The rebalance … Read more
One reason is that it is easy to create a set from map: s := map[int]bool{5: true, 2: true} _, ok := s[6] // check for existence s[8] = true // add element delete(s, 2) // remove element Union s_union := map[int]bool{} for k, _ := range s1{ s_union[k] = true } for k, _ … Read more