Lecture 10: Dijkstra’s Shortest Path Algorithm
www.cse.ust.hk › ~dekai › 271Lecture 10: Dijkstra’s Shortest Path Algorithm CLRS 24.3 Outline of this Lecture Recalling the BFS solution of the shortest path problem for unweighted (di)graphs. The shortest path problem for weighted digraphs. Dijkstra’s algorithm. Given for digraphs but easily modified to work on undirected graphs. 1
Proof for Dijkstra’s Algorithm - UC Davis
web.cs.ucdavis.edu › ~amenta › w10i to be the length of the shortest path from s to vertex v i. Dijkstra’s algorithm maintains a set of vertices S, with two properties. First, S is a set of vertices in the graph nearest to s; that is: ∀v i ∈ S, ∀v j ∈ V −S, d i ≤ d j And second, for all vertices v j ∈ S, there is a shortest path from s to v j using only vertices ...
Lecture 13: Dijkstra’s Algorithm - MIT OpenCourseWare
ocw.mit.edu › courses › 6-006-introduction-to• Claim: At end of Dijkstra’s algorithm, d(s, v) = δ(s, v) for all v ∈ V • Proof: – If relaxation sets d(s, v) to δ(s, v), then d(s, v) = δ(s, v) at the end of the algorithm ∗ Relaxation can only decrease estimates d(s, v) ∗ Relaxation is safe, i.e., maintains that each d(s, v) is weight of a path to v (or ∞)
Shortest Paths - Princeton University
www.cs.princeton.edu › shortest-pathDijkstra's Algorithm With Negative Costs Dijkstra's algorithm fails if there are negative weights. Ex: Selects vertex immediately after s. But shortest path from sto vis s-x-y-v. Challenge: shortest path algorithm that works with negative costs. Dijkstra proof of correctness breaks down since it assumes cost of P is nonnegative. s v x 2 4-9 y 6 ...