Nonnegative Integer Weights: Difference between revisions

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[[File:Shortest Path (Directed Graphs) - Nonnegative Integer Weights - Space.png|1000px]]
[[File:Shortest Path (Directed Graphs) - Nonnegative Integer Weights - Space.png|1000px]]


== Space-Time Tradeoff Improvements ==  
== Time-Space Tradeoff ==  


[[File:Shortest Path (Directed Graphs) - Nonnegative Integer Weights - Pareto Frontier.png|1000px]]
[[File:Shortest Path (Directed Graphs) - Nonnegative Integer Weights - Pareto Frontier.png|1000px]]

Revision as of 14:41, 15 February 2023

Description

The shortest path problem is the problem of finding a path between two vertices (or nodes) in a graph such that the sum of the weights of its constituent edges is minimized. Here, the weights are restricted to be nonnegative integers.

Related Problems

Generalizations: nonnegative weights

Related: General Weights, Nonnegative Weights, Second Shortest Simple Path, st-Shortest Path, 1-sensitive (3/2)-approximate ss-shortest paths, 2-sensitive (7/5)-approximate st-shortest paths, 1-sensitive decremental st-shortest paths, 2-sensitive decremental st-shortest paths, Replacement Paths Problem

Parameters

V: number of vertices

E: number of edges

L: maximum absolute value of edge cost

Table of Algorithms

Name Year Time Space Approximation Factor Model Reference
Dijkstra's algorithm with Fibonacci heap (Johnson ; Karlsson & Poblete 1983) 1981 $O(E log log L)$ $O(V+L)$ Exact Deterministic Time & Space
Gabow Ahuja Algorithm 1990 $O(E + V*((log(L))^{0.5}) )$ $O(m + log C)$ Exact Deterministic Time & Space
Thorup's algorithm 2004 $O(E + V min(log log V, log log L))$ $O(V)$? ("linear-space queue") Exact Deterministic Time & Space

Time Complexity Graph

Shortest Path (Directed Graphs) - Nonnegative Integer Weights - Time.png

Space Complexity Graph

Shortest Path (Directed Graphs) - Nonnegative Integer Weights - Space.png

Time-Space Tradeoff

Shortest Path (Directed Graphs) - Nonnegative Integer Weights - Pareto Frontier.png

References/Citation

https://dl.acm.org/doi/10.1016/j.jcss.2004.04.003