What is the time complexity of dynamic memory allocation using new, malloc, etc.? I know very little about how memory allocators are implemented, but I assume the answer is that it depends on the implementation. Therefore, please answer for some of the more common cases/implementations. Edit: I vaguely remember hearing that heap allo...
Well, I have this bit of code that is slowing down the program hugely because it is linear complexity but called a lot of times making the program quadratic complexity. If possible I would like to reduce its computational complexity but otherwise I'll just optimize it where I can. So far I have reduced down to: def table(n): a = 1 ...
Hello, how expensive is it to perform the dereference operation on a pointer in C++? I can imagine that the memory transfer is somehow proportional to the object size, but I want to know how expensive the dereference operation part is. Thank you. ...
Is there a widely-used algorithm that has time complexity worse than that of another known algorithm but it is a better choice in all practical situations (worse complexity but better otherwise)? An acceptable answer might be in a form: There are algorithms A and B that have O(N**2) and O(N) time complexity correspondingly, but...
Okay this is not a question of "how to get all uniques" or "How to remove duplicates from my array in php". This is a question about the time complexity. I figured that the array_unique is somewhat O(n^2 - n) and here's my implementation: function array_unique2($array) { $to_return = array(); $current_index = 0; for ( $i =...
Given a n*n-sized multi-headed acyclic graph where each node has at most three children and three parents, is there an non-exponential algorithm to identify whether a n-length path exists where no two nodes share the same value, and every value of a set is accounted for? Basically, I have an n*n maze where each space has a random value ...
i have coded an algorithm for search in sorted array with complexity log2(n)/5 .Is it useful? ...
What all algorithms do you people find having amazing (tough, strange) complexity analysis in terms of both - Resulting O notation and uniqueness in way they are analyzed? ...
I haven't seen anything out there, and I suspect the difficulty with defining "n" since for generally for analyzing a complex function there'd be more than just one or two variables for defining. There are analysis tools for cyclomatic complexity but are there ones for time (and/or space) complexity? If so which ones, if not, why not...
I was looking at the Wikipedia entry for Prim's algorithm and I noticed that its time complexity with an adjacency matrix is O(V^2) and its time complexity with a heap and adjacency list is O(E lg(V)) where E is the number of edges and V is the number of vertices in the graph. Since Prim's algorithm is used in denser graphs, E can appro...
Given an input set of n integers in the range [0..n^3-1], provide a linear time sorting algorithm. This is a review for my test on thursday, and I have no idea how to approach this problem. ...
I think it is MergeSort, which is O(n log n). However, the following output disagrees: -1,0000000099000391,0000000099000427 1,0000000099000427,0000000099000346 5,0000000099000391,0000000099000346 1,0000000099000427,0000000099000345 5,0000000099000391,0000000099000345 1,0000000099000346,0000000099000345 I am sorting a nodelist of 4 no...
Can anyone help with with the time complexity of this algorithm, and why it is O(n^2). A step by step explanation would be helpful, thanks! function divide(x,y) Input: Two n-bit integers x and y, where y >= 1 Output: The quotient and remainder of x divided by y if x = 0: return (q,r) = (0,0) (q,r) = divide(x/2,...
I am currently working on a project for the iPhone that requires accessing a large amount of hierarchical data stored in a local sqlite database. One of the more common operations is calculating a rollup status field. Right now, I'm doing that by recursing through all the descendants of that item (which can be anywhere from 1 to n levels...
Can someone please explain to me how one can determine the worst-case complexity of an algorithm. I know that the we need to use the equation W(n) = max{t(I)|I element of D), where D is the set of inputs of size n. Do I calculate the number of operations performed for each element I and then take its max? What easier way is there to acco...
As the title asks, I wonder if the size() method in the LinkedList class takes amortized O(1) time or O(n) time. Thanks! ...
i need a datastructure in dotnet where i can search an item in constant time.it means that datastructure should implement indexing internally.is dictionary usefull for this purpose or some other one? ...
Hi, I am trying to get the worst run-time complexity order on a couple of algorithms created. However I have run into a problem that I keep tending to select the wrong or wrong amount of fundamental operations for an algorithm. To me it appears to be that the selection of the fundamental operation is more of an art than a science. Afte...
I was going through some data structures and I noticed this as a time complexity: O(log(log(n))))-competitive. I read that constant-competitive was the ratio of the expected time/optimal time. But what does it mean to have a set-competitive? ...
Hi All, I'm trying to evaluate the complexity of some basic image filtering algorithms. I was wondering if you could verify this theory; For a basic pixel by pixel filter like Inverse the number of operations grows linearly with the size of the input (In pixels) and Let S = Length of the side of the image Let M = # pixels input Inve...