Graph Algorithm Visualizer (JavaFX)

An interactive JavaFX application that visualizes common graph algorithms step-by-step.
Supports BFS, DFS, and Dijkstra’s shortest path with real-time simulation, node state coloring, traversal order labels, and shortest-path highlighting.

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Features

✅ Algorithms

• BFS (Breadth-First Search) — press B
• DFS (Depth-First Search) — press D
• Dijkstra (Shortest Path on weighted graph) — click START + TARGET, then press J

✅ Visualization

• Node states:
  • Blue = unvisited
  • Yellow = discovered / in queue (frontier)
  • Green = visited / processed
• Traversal order numbers displayed on visited nodes
• Dijkstra displays:
  • tentative distances during execution
  • final shortest path highlighted
  • total path cost shown in the window
• On-screen HUD/guide explaining key controls

✅ Interaction

• Click nodes to select Dijkstra endpoints:
  • START = purple
  • TARGET = red
• Dijkstra runs until TARGET is finalized, then reconstructs and highlights the shortest path

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Controls

Action	Input
Run BFS	B
Run DFS	D
Select START node (Dijkstra)	click a node
Select TARGET node (Dijkstra)	click a different node
Run Dijkstra	J

Tip: After running Dijkstra, pressing B or D clears the START/TARGET selection and any highlighted shortest path.

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Project Structure

GraphVisualizer/ └── src/ └── app/ ├── MainApp.java ├── GraphNode.java ├── Edge.java ├── BFSAlgorithm.java ├── DFSAlgorithm.java └── DijkstraAlgorithm.java

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Requirements

• Java 17+ recommended (Java 21+ works great)
• JavaFX SDK (e.g. JavaFX 23)
• Windows/macOS/Linux supported

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How to Run (PowerShell / Windows)

From the src directory:

Compile

javac --module-path "C:\javafx\javafx-sdk-23.0.2\lib" --add-modules=javafx.controls,javafx.fxml app/*.java

Run

java --module-path "C:\javafx\javafx-sdk-23.0.2\lib" --add-modules=javafx.controls,javafx.fxml app.MainApp

If your JavaFX path is different, update the --module-path value.

Notes

BFS/DFS use an unweighted adjacency list.

Dijkstra uses a weighted adjacency list with a priority queue, and stores predecessors (prev) to reconstruct the final shortest path.

The code separates algorithm logic from UI for clean design and easy extension (e.g., add A*, Bellman-Ford, etc.).

Future Improvements

UI buttons (Play/Pause/Step)

Click-to-start BFS/DFS as well

A* search visualization

Random graph generator / import graph from file

Display queue/stack/priority queue contents in the HUD