Introduction to the A* Algorithm

Amit Patel's visual tutorial builds A* from the ground up, letting grid diagrams carry the intuition while compact code keeps the lesson honest. It starts with breadth-first search, adds movement costs and heuristics, then shows why A* balances speed with a reliable shortest path.

What is Introduction to the A* Algorithm?

This is an algorithm lesson with unusually good stagecraft. The page begins by reducing a map to nodes and edges, then walks the same grid through breadth-first search, early exits, weighted movement, Dijkstra's algorithm, Greedy Best-First Search, and finally A*. Along the way, diagram controls invite you to move the endpoints, watch a search frontier spread, and compare how much territory each method explores. Small Python snippets sit beside the pictures, so the concepts never float too far from something you could implement. A separate companion guide takes the next step into fuller Python, C++, and C# examples.

What you can do there

• Move start and goal markers across grid examples
• Play and step through search-frontier diagrams
• Compare breadth-first, Dijkstra, greedy, and A* search

Why we picked it

The page makes the tradeoffs visible before asking you to memorize terminology. Its best trick is pacing: each new algorithm fixes a limitation you just encountered, so A* arrives as a sensible compromise instead of a magic formula dropped from the ceiling.

How to get the most from it

Read in order and pause at every comparison. First predict which cells the next search will inspect, then use the available diagram control to check your guess. When the A* section clicks, continue to the companion implementation guide and translate one example into your own graph type.

Good to know

This is a substantial, code-adjacent lesson rather than a two-minute definition. It explains search, not the entire movement stack: changing obstacles, object size, animation, smoothing, and coordinated motion sit outside its scope. The diagram controls favor direct manipulation, while keyboard, touch, screen-reader, and reduced-motion behavior are undocumented.

Who made it, and when?

Amit J. Patel is the credited creator or organization. The earliest supported launch date we found is May 26, 2014. A documented update was recorded June 5, 2026.