Fast Algorithms for Solving Path Problems

Research output: Contribution to journalArticlepeer-review

196 Scopus citations


Let G = (V, E) be a directed graph with a distinguished source vertex s. The single-source path expression problem is to find, for each vertex v, a regular expression P(s, v) which represents the set of all paths in G from s to v A solution to this problem can be used to solve shortest path problems, solve sparse systems of linear equations, and carry out global flow analysis. A method is described for computing path expressions by dwidmg G mto components, computing path expressions on the components by Gaussian elimination, and combining the solutions This method requires O(ma(m, n)) time on a reducible flow graph, where n Is the number of vertices m G, m is the number of edges in G, and a is a functional inverse of Ackermann's function The method makes use of an algonthm for evaluating functions defined on paths in trees. A smapllfied version of the algorithm, which runs in O(m log n) time on reducible flow graphs, is quite easy to implement and efficient m practice.

Original languageEnglish (US)
Pages (from-to)594-614
Number of pages21
JournalJournal of the ACM (JACM)
Issue number3
StatePublished - Jul 1 1981
Externally publishedYes

All Science Journal Classification (ASJC) codes

  • Software
  • Artificial Intelligence
  • Information Systems
  • Control and Systems Engineering
  • Hardware and Architecture


  • Ackermann's function
  • Gaussian ehmmation
  • code optimization
  • compdmg
  • dominators
  • global flow analysis
  • graph algorithm
  • linear algebra
  • path compression
  • path expression
  • path problem
  • path sequence
  • reducible flow graph
  • regular expressmn
  • shortest path
  • sparse matrix


Dive into the research topics of 'Fast Algorithms for Solving Path Problems'. Together they form a unique fingerprint.

Cite this