csnotes/370/notes/a-star.md

A* Pathfinding

There are 3 main values usedd in reference to A*:

f = how promisiing a new location is
g = distance from origin
h = estimate distance to goal
f = g + h

For a grid space our h is calculated by two straight shots to the goal from the current location(ignore barriers). The grid space g value is basiccally the number of steps we've taken from the origin. We maintain a list of potential nodes only, so if one of the seeking nodes gets us stuck we can freely remove that, because it succs.

Time & Space Commplexities

Best-First Search

Time: O(VlogV + E)

Dijkstra's

O(V)

A*

O(V^2 = E)