In computer science, Prim’s algorithm (also known as Jarník’s algorithm) is a greedy algorithm Greedy algorithm] that finds a minimum spanning tree [Minimum spanning tree] for a weighted undirected graph [Graph]. This means it finds a subset of the edges that forms a tree that includes every vertex, where the total weight of all the edges in the tree is minimized. The algorithm operates by building this tree one vertex at a time, from an arbitrary starting vertex, at each step adding the cheapest possible connection from the tree to another vertex.

(“Prim’s Algorithm” 2022)


The algorithm may informally be described as performing the following steps:

  1. Initialize a tree with a single vertex, chosen arbitrarily from the graph.
  2. Grow the tree by one edge: of the edges that connect the tree to vertices not yet in the tree, find the minimum-weight edge, and transfer it to the tree.
  3. Repeat step 2 (until all vertices are in the tree).

(“Prim’s Algorithm” 2022)

Time complexity


“Prim’s Algorithm.” 2022. Wikipedia, December.