Graphs and Network Algorithms · Minimum Spanning Trees

Prim's Algorithm

Prim's algorithm grows a minimum spanning tree outward from a starting vertex by repeatedly choosing the cheapest crossing edge.

Student Focus

We teach Prim as the vertex-frontier view of minimum spanning trees.

Guided Lesson Notes

How Code Scholars teaches Prim's Algorithm

This guide helps students understand the idea, implement it carefully, explain the runtime, and recognize when the pattern belongs in a larger problem.

In a session, students usually start with a small trace, then write or review code, then test edge cases. The final step is a short explanation: what the structure or algorithm stores, why it is correct, and what changes when the input grows.

Key Ideas

  • Growing tree frontier
  • Priority queue edge choice
  • Cut intuition

Practice Prompts

  • Trace Prim from two different starting vertices.
  • Compare Prim and Kruskal on the same graph.

Tutoring Connection

Turn the topic into usable problem-solving skill

Students can use this page before a lesson, after a difficult homework assignment, or while preparing for AP Computer Science A extensions, Advanced Topics in CS, USACO growth, or a college data structures course.