There is a beautiful structure called an extendible array that has worst-case O(1) insertion and O(n) memory overhead (that is, it’s asymptotically comparable to a dynamic array, but has O(1) worst-case insertion). The trick is to take the approach that the vector uses – doubling and copying – but to make the copying lazy. For … Read more
There’s a beautiful algorithm for solving this problem in time O(n + Sort), where Sort is the amount of time required to sort the input array. The idea behind the algorithm is to sort the array and then ask the following question: what is the smallest positive integer you cannot make using the first k … Read more
I don’t think that this task is a “wheel” (so to speak). But it is something which you can easily achieve by means of the tools you mentioned: import os import json def path_to_dict(path): d = {‘name’: os.path.basename(path)} if os.path.isdir(path): d[‘type’] = “directory” d[‘children’] = [path_to_dict(os.path.join(path,x)) for x in os.listdir\ (path)] else: d[‘type’] = “file” … Read more
Because in the course of normal operations Python will create and destroy a lot of small tuples, Python keeps an internal cache of small tuples for that purpose. This helps cut down on a lot of memory allocation and deallocation churn. For the same reasons small integers from -5 to 255 are interned (made into … Read more
You can use SelectMany and then ToArray to do this. var result = source.SelectMany(i => i).ToArray();
Your question seems to be well answered here but to summarise in relation to your specific question it might be better to think of it in reverse; “what happens to the BST solution time as the number of nodes goes up”? Essentially, in a BST every time you double the number of nodes you only … Read more
In C++ a class with at least one pure virtual function is called abstract class. You can not create objects of that class, but may only have pointers or references to it. If you are deriving from an abstract class, then make sure you override and define all pure virtual functions for your class. From … Read more
They are semantically different. Consider: #include <set> #include <map> #include <utility> #include <iostream> using namespace std; int main() { pair<int, int> p1(1, 1); pair<int, int> p2(1, 2); set< pair<int, int> > s; s.insert(p1); s.insert(p2); map<int, int> m; m.insert(p1); m.insert(p2); cout << “Set size = ” << s.size() << endl; cout << “Map size = ” … Read more
As far as I know, Idris (a dependently-typed purely functional language which is very close to Haskell) deals with this in a quite straightforward way. Compiler is aware of Nats and Fins (upper-bounded Nats) and replaces them with machine integer types and operations whenever possible, so the resulting code is pretty effective. However, that’s not … Read more
The author of the SQLite implementation has disclaimed copyright. If LGPL is okay, then maybe you could use GNUpdate’s implementation?