It says A* is faster than using dijkstra and uses best-first-search to speed things up. A* is basically an informed variation of Dijkstra. A* is considered a "best first search" because it greedily chooses which vertex to explore next, according to the value of f(v) [f(v) = h(v) + g(v)] - where h is the heuristic and g is the cost so far. Note that if you use a non informative heuristic ...
I'm learning the Dijkstra algorithm and I am testing out this code from GeeksforGeeks. I want the program to print the path for the shortest distance between 2 nodes as well. I defined: int parent[...
As per my understanding, I have calculated time complexity of Dijkstra Algorithm as big-O notation using adjacency list given below. It didn't come out as it was supposed to and that led me to unde...
Dijkstra's algorithm is definitely complete and optimal that you will always find the shortest path. However it tends to take longer since it is used mainly to detect multiple goal nodes.
Therefore, dijkstra has the advantage over A* which is that it works for any general graph (with the exception of A* being faster in some cases). It could well be that certain implementations use these algorithms interchangeably, resulting in different results.
Variants of Dijkstra's Algorithm The key is there are 3 kinds of implementation of Dijkstra's algorithm, but all the answers under this question ignore the differences among these variants. Using a nested for -loop to relax vertices. This is the easiest way to implement Dijkstra's algorithm. The time complexity is O (V^2).
I was reading about worst case time complexity for the Dijkstra algorithm using binary heap (the graph being represented as adjacency list). According to Wikipedia and various stackoverflow questions, this is O((V + E) logV) where E - number of edges, V - number of vertices.
I am reading up on Dijkstra's algorithm and the Floyd-Warshall algorithm. I understand that Dijkstra's finds the optimal route from one node to all other nodes and Floyd-Warshall finds the optimal route for all node pairings.
The Dijkstra algorithm finds the shortest path in a graph. So if you want to modify this algorithm to find the longest path in a graph, then you just have to multiply the edge weight by "-1". With this change the shortest path will be actualy the longest path. If you want to extract the result, just multiply the result by "-1". Here is an example:
