The standard answer is to take two iterators at the beginning, increment the first one once, and the second one twice. Check to see if they point to the same object. Then repeat until the one that is incrementing twice either hits the first one or reaches the end. This algorithm finds any circular link … Read more
The feature data you mention (position, laplacian, size, orientation, hessian) is insufficient for your purpose (these are actually the less relevant parts of the descriptor if you want to do matching). The data you want to look at are the “descriptors” (the 4th argument): void cvExtractSURF(const CvArr* image, const CvArr* mask, CvSeq** keypoints, CvSeq** descriptors, … Read more
It’s implementation specific. All a deque requires is constant time insertion/deletion at the start/end, and at most linear elsewhere. Elements are not required to be contiguous. Most implementations use what can be described as an unrolled list. Fixed-sized arrays get allocated on the heap and pointers to these arrays are stored in a dynamically sized … Read more
In Computing Science terminology, a map is an associative container mapping from a key to a value. In other words, you can do operations like “for key K remember value V” and later “for key K get the value”. A map can be implemented in many ways – for example, with a (optionally balanced) binary … Read more
This may not be the answer to your problem but it was to mine: http://mediainfo.sourceforge.net/ (It has a library and it’s open source so you can just check for the part(s) you need)
All file systems are different, so there are a huge number of data structures that actually get used in file systems. Many file systems use some sort of bit vector (usually referred to as a bitmap) to track where certain free blocks are, since they have excellent performance for querying whether a specific block of … Read more
No, the standard Java collections API does not contain an implementation of a Fibonacci heap. I’m not sure why this is, but I believe it is because while Fibonacci heaps are asymptotically great in an amortized sense, they have huge constant factors in practice. The collections framework also doesn’t have a binomial heap, which would … Read more
Label each node and make an edge list. That is, for each node store the nodes that it has edges to, for example: { “a”: [ “b”, “c”, “d” ], “b”: [ “d” ], “c”: [ “d” ], “d”: [ ] } You can store many kinds of graphs this way, not just DAGs, so … Read more
They offer a clean abstraction over data updates, and are never really “needed.” They just let you reason about a problem in a different way. In some imperative/”object-oriented” programming languages like C, you have the familiar concept of some collection of values (let’s call them “structs”) and ways to label each value in the collection … Read more
Using Map<E, Integer> where Integer is the count is a good replacement for Multiset, and it does not need any third party library as well. Update: If you really want to store the object twice, use a List with a Map like Map<E, List<E>>.