Breadth-First Search

Breadth-first Search (BFS) is an algorithm used to explore the vertexes of a graph layer by layer. It starts at the given vertex and explores all vertices at the present depth prior to moving on to the vertices at the next depth level.


CREATE QUERY tg_bfs(SET<STRING> v_type, SET<STRING> e_type,INT max_hops=10,
    VERTEX v_start, BOOL print_accum = True, STRING result_attr = "",
    STRING file_path = "", BOOL display_edges = True)
Characteristic Value


Returns all the nodes that are accessible from the source vertex

Required Input Parameters

  • v_type: vertex types to traverse

  • e_type: edge types to traverse

  • max_hops: look only this far from each vertex

  • v_start: source vertex for traversal

  • print_accum: print JSON output

  • result_attr: INT attr to store results to

  • file_path: file to write CSV output to

  • display_edges:output edges for visualization

Result Size

V = number of vertices

Time Complexity

O(E+V), E = number of edges, V = number of vertices.since every vertex and every edge will be explored in the worst case.

Graph Types

Directed or Undirected edges, Weighted or Unweighted edges


In the example below, we run tg_bfs algorithm from the source vertex alex on the social10 graph.

# Use _ for default values
RUN QUERY tg_bfs(["Person"], ["Friend"], _, ("Alex","Person"), _, _, _, _)

Below is the visualized result of the query:

bfs ex