Dijkstra's algorithm - Dijkstra's algorithm Dijkstra's algorithm, named after its inventor the Dutch computer scientist Edsger Dijkstra, solves a shortest path problem for a directed and connected graph G(V,E) which has nonnegative (>=0) edge weights. The set V is the set of all vertices in the graph G. The set E is the set of ordered pairs which represent connected vertexes in the graph (if (u,v) belongs to E then there is a connection from vertex u to vertex v). Assume that the function w: V x V -> [0, â] describes the cost w(x,y) of moving from vertex x to vertex y (non-negative cost). (We can define the cost to be infinite for pairs of vertices that are not connected by an edge.) The cost of a path.
Edsger Dijkstra - Edsger Dijkstra zh-cn:艾兹格ˇWˇ迪科斯彻 Image of Edsger Dijkstra courtesy of Brian Randell. Edsger Wybe Dijkstra (May 11, 1930 - August 6, 2002) was a Dutch computer scientist. Dijkstra studied theoretical physics at the University of Leiden. He worked as a research fellow for Burroughs Corporation in the early 1970s. He held the Schlumberger Centennial Chair in Computer Sciences at the University of Texas at Austin, in the United States. He retired in 2000. Among his contributions to computer science are the shortest path-algorithm, also known as Dijkstra's algorithm. He received the Turing Award in 1972. He was known for his low opinion of the GOTO statement in computer programming, culminating in the 1968 article Go To Statement Considered Harmful, which is regarded as a major step towards the.
Bellman-Ford algorithm - Bellman-Ford algorithm Bellman-Ford algorithm computes single-source shortest paths in a weighted graph (where some of the edge weights may be negative). Dijkstra's algorithm accomplishes the same problem with a lower running time, but requires edges to be non-negative. Thus, Bellman-Ford is usually used only when there are negative edge weights. Bellman Ford runs in O(VE) time, where V and E are the number of vertices and edges. Here is a sample algorithm of Bellman-Ford BF(G,w,s) // G = Graph, w = weight, s=source Determine Single Source(G,s); set Distance(s) = 0; Predecessor(s) = nil; for each vertex v in G other than s, set Distance(v) = infinity, Predecessor(v) = nil; for i <- 1 to V(G) - 1 do //V(G) Number of vertices in the graph for each edge.
List of algorithms - in Wikipedia. See also the list of data structures. If you intend to describe a new algorithm, please read algorithms on Wikipedia first, then add a link to your article and a one-line description here. Compression algorithms: Arithmetic coding: advanced entropy coding Burrows-Wheeler transform: preprocessing useful for lossless compression DEFLATE: lossless data compression Delta encoding: aid to compression of data in which sequential data occurs oftenly Huffman coding: simple lossless entropy coding LZW: lossless data compression Run-length encoding: lossless data compression Cryptographic algorithms: Symmetric (secret key) encryption: AES Blowfish DES IDEA RC4 Asymmetric (public key) encryption or digital signature: DSA ElGamal RSA Message digest: MD5 RIPEMD-160 SHA-1 Other: Diffie-Hellman: key exchange HMAC: keyed-hash message authentication Distributed systems algorithms: Lamport ordering: a partial ordering of events based on the happened-before relation Snapshot.
Graph theory - in computer science. Table of contents showTocToggle("show","hide") 1 History 2 Graph problems 3 Important algorithms 4 Generalizations 5 Related areas of mathematics 6 See also History Leonhard Euler's paper on Seven Bridges of Königsberg is considered to be the first result in graph theory. It is also regarded as one of the first topological results in geometry; that is, it does not depend on any measurements. This illustrates the deep connection between graph theory and topology. Graph problems Graph coloring: the four color theorem Route problems: Seven bridges of Königsberg Minimum spanning tree Shortest path problem Route inspection problem (also called the "Chinese Postman Problem") Traveling salesman problem Flows: Max flow min cut theorem reconstruction conjecture Isomorphism problems (Graph matching) Canonical Labeling subgraph isomorphism and monomorphisms Maximal common subgraph Important algorithms.
Diablo II - for the profit of the cheaters. Another type of hack that is very popular is maphack. This hack allows the user to see the entire game map and all the monsters. This gives the player an advantage because they know where to find the monsters and which monsters they should avoid. The most popular creator of the Diablo II maphack is mousepad. The most controversial type of hacks on the realm are the so called "bugged" or "hacked" items. It is unclear how these items first appeared on the realm. Some of these items with extraordinarily powerful effects were created by hack programs and bugs in the game. These are generally referred to as "bugged" items. The "hacked" items have characteristics that are too powerful to have resulted from an accident,.
Dining philosophers problem - is an illustrative example of a common computing problem. In 1965, Edsger Dijkstra used the example of a group of philosophers to solve a synchronization problem. Five philosophers are sitting around a circular table and each has a plate of spaghetti in front of him with a fork either side (i.e. five philosophers, five plates, and five forks). Suppose that the life of a philosopher consists of periods of eating and thinking, that each philosopher needs two forks to eat, and that forks are picked up one at a time. After successfully picking up two forks, a philosopher eats for a while and then puts down the forks and thinks. The problem consists in developing an algorithm to avoid starvation and deadlock. Deadlock might occur if each of the five philosophers.
August 2002 - $50 million in emergency aid in response to the $300 million in damage of northern Italy's crops. US Airways declares bankruptcy, caused by the air travel slowdown following the September 11, 2001 Terrorist Attack. Colombian president Alvaro Uribe declares state of emergency. August 11, 2002 UNEP (UN Environment Programme) reports on the Asian brown cloud. August 10, 2002 Charlton Heston, movie actor and president of the National Rifle Association, announces that he has Alzheimer's disease August 9, 2002 Extreme weather: Dozens are killed by floods caused by torrential rains in Europe, including the Malse and Blanice rivers of the Czech Republic, the Black Sea resort village of Shirokaya Balka near Novorossiisk in Russia, and Romania. The downpours have also caused extensive damage in Austria, Bulgaria, Croatia, Italy, and Spain. A massive.
Best-first search - Best-first search is a search algorithm which optimises breadth first search by ordering all current paths according to some heuristic. The heuristic attempts to predict how close the end of a path is to a solution. Paths which are judged to be closer to a solution are extended first. Efficient selection of the current best candidate for extension is typically implemented using a priority queue. Examples of best-first search algorithms include Dijkstra's algorithm and the A-star search algorithm. Best-first algorithms are often used for pathfinding in combinatorial search. See also Breadth-first search Depth-first search Iterative deepening depth-first search.
Control flow - which is attached to a statement by using a colon ':', e.g. Success:print("target has been found") Historical note: Algol 60 allowed both whole numbers and identifiers as labels (both attached by colons to statements), but few if any implementations allowed whole numbers. Goto The most common form for the unconditional transfer of control is just goto label Conditional transfer of control varies from language to language, e.g. IF test THEN label IF (test) GOTO label if test then goto label; if (test) goto label; For a fuller discussion on the drawbacks of goto, see Goto. In brief, undisciplined use of goto leads to spaghetti code which tends to be unmaintainable; see Edsger Dijkstra's comments in Go to statement considered harmful. However, Donald Knuth has shown in Structured Programming with goto statements.
Timeline of computing 1950-1979 - machine used magnetic tape for input. 1951 CSIRAC used to play music - the first time a computer was used as a musical instrument. 1952 IAS machine completed at the Institute for Advanced Study, Princeton, USA (by Von Neumann and others). 1953 The University of Manchester team complete the first transistorised computer. 1953 Estimate that there are 100 computers in the world. 1953 Magnetic core memory developed. 1954 FORTRAN (FORmula TRANslation) development started by John Backus and his team at IBM - continuing until 1957. FORTRAN was the first high-level programming language, still in use for scientific programming. Before being run, a FORTRAN program needs to be converted into a machine program by a compiler, itself a program. 1956 First conference on Artificial Intelligence held at Dartmouth College in New Hampshire..
Shortest path problem - f : E -> R), and given further two elements n, n' of N, find a path P from n to n', so that is minimal among all paths connecting n to n'. A solution to the shortest path problem is sometimes called a "pathing algorithm". The most important algorithm for solving this problem in case all edge weights are greater than or equal to zero is Dijkstra's algorithm. Without worsening the run time, this algorithm can in fact compute the shortest paths from a given start point s to all other nodes. Another algorithm is the A* algorithm (or A* pathing algorithm.) A related problem is the traveling salesman problem, which is the problem of finding the shortest path that goes through every node exactly once, and returns to the.
Smoothsort - Smoothsort The smoothsort sorting algorithm is a variation of heapsort developed by Edsger Dijkstra. The advantage of smoothsort is that it works in O(n) time if the input is (almost) sorted. Due to the extra complexity it is rarely used. External references: http://www.cs.utexas.edu/users/EWD/ewd07xx/EWD796a.PDF.
Open shortest path first - hierarchical Interior Gateway Protocol (IGP) routing algorithm. The well known Dijkstra's algorithm is used to calculate the shortest path tree. It uses cost as its routing metric. A link state database is constructed of the network topology which is identical on all routers. An OSPF network can be broken up into smaller networks where a backbone always known as area zero can have any other arbitrarily numbered areas connecting directly to it. All areas must connect via area zero. Virtual links are an exception to this but they are not recommended. It was often a general rule not to have more than fifty routers in one area. However, improvements in processor power can now allow over 400 sufficiently powerful routers to participate with no stability issues. Routers at the edge of.
Mutual exclusion - which one process gets a semaphore, another process gets a semaphore, and then both wait forever for the other semaphore to be released. Other common side-effects include "starvation," in which an essential process does not run enough, and "priority inversion" in which a higher priority task waits for a lower-priority task, and "high latency" in which response to interrupts is not prompt. Much research attempts to eliminate the above effects. No perfect scheme is known. One intriguing non-classical scheme sends messages between pieces of code. This permits priority inversions, and increases latency but makes deadlocks unlikely. Examples of classical mutex algorithms include: Dekker's algorithm Peterson's algorithm See also: Edsger Dijkstra's Semaphores (very simple!) C. A. R. Hoare's Monitors (no deadlocks!).
List of computing topics - -- Ada programming language -- Advanced Optical Disk (AOD) -- AIM alliance -- AirPort networking -- AIX operating system -- Alan programming language -- Algol -- Algol 60 -- Algol programming language -- AltiVec -- Amdahl's law -- America Online -- Amiga -- AmigaE -- Analysis of algorithms -- AOL -- APL programming language -- Apple Computer -- Apple II -- Apple Macintosh -- AppleScript -- Arithmetic and logical unit -- ASCII -- Assembly language -- Atari -- Atlas Autocode -- AutoLISP -- Automaton -- AWK -- B -- B Backus-Naur Form -- Basic Rate Interface (2B+D)-- BASIC -- Basic Object System -- batch job -- BCPL -- Befunge -- BeOS -- Berkeley Software Distribution -- BETA -- Big Mac -- Big O notation -- Binary symmetric channel -- Binary Synchronous.
Link-state routing protocol - all of its neighbors who in turn send it to all of their neighbors and so on. Soon, all routers on the network have this information. The neighbor information is flooded whenever there is a (routing-significant) change in the network. As every router knows everything about the network by structuring the information from other routers, it can calculate the best path to any host on any destination network by using Dijkstra's algorithm..
List of mathematical topics (D-F) - matrix -- Depth-first search -- Derangement -- Derivation -- Derivative -- Derivative of a constant -- Derived functor -- Derived group -- DES -- Girard Desargues -- Desargues' theorem -- Descartes, René -- Descent (category theory) -- Descriptive statistics -- De Sitter space -- Determinant -- Determinant mathematics -- Deterministic universe -- Devil's staircase -- Diagnostic variables -- Diagonal -- Diagonalization -- Diameter -- Diamond theory -- Dice -- Dickson's lemma -- Dictionary attack -- Dicyclic group -- Diffeology -- Diffeomorphism -- Difference equation -- Difference operator -- Differential calculus -- Differential equation -- Differential equations of mathematical physics -- Differential form -- Differential geometry -- Differential operator -- Differential rotation -- Differential topology -- Differintegral -- Diffie, Whitfield -- Diffie-Hellman -- Digamma function -- Digit -- Digital Signature Algorithm --.
List of graph theory topics - coloring Bipartite graphs Disperser Expander Extractor Four color theorem Tait's conjecture Ramsey's theorem Paths and cycles Seven bridges of Königsberg Shortest path problem Dijkstra's algorithm Open shortest path first Flooding algorithm Route inspection problem Hamiltonian cycle problem, Hamiltonian path Knight's Tour How to solve the knight's tour Traveling salesman problem Nearest neighbour algorithm Trees Tree (graph theory) Terminology Root node, root (computing) Leaf node Child node, parent node Ply Tree structure Tree data structure AVL tree B-tree Binary tree Binary search tree Heap Binary heap Binomial heap Fibonacci heap Red-black tree Splay tree Tree rotation Trie Examples Abstract syntax tree Decision tree Evolutionary tree Family tree Game tree Parse tree Phylogenetic tree Technology tree Spanning tree Minimum spanning tree Boruvka's algorithm Kruskal's algorithm Prim's algorithm Tree traversal Inorder traversal Backward inorder.
Kahan summation algorithm - Kahan summation algorithm In numerical analysis, the Kahan summation algorithm minimizes the error when adding a sequence of finite precision floating point numbers. It is of basic use, therefore, on computers. It is also called compensated summation. As the name suggests, this algorithm is attributed to William Kahan..
