I don't think this is true. From Wikipedia [1]: > The heuristic function is problem-specific. If the heuristic function is admissible, meaning that it never ov

I don't think this is true. From Wikipedia [1]: > The heuristic function is problem-specific. If the heuristic function is admissible, meaning that it never overestimates the actual cost to get to the goal, A* is guaranteed to return a least-cost path from start to goal. In this case the euclidean does not overestimate so I would guess there is a bug in the implementation. [1] https://en.wikipedia.org/wiki/A*_search_algorithm https://en.wikipedia.org/wiki/A*_search_algorithm Edit: Having taken a look at the source code I believe the problems mostly stem from the `addNeighboursToOpen` function [2]. It sets the distance and parent of unvisited neighbors of the current node. However this may happen multiple times for a node before it is actually visited. Meaning that the distance and parent is updated multiple times and the value at the end is not the optimal one. A simple fix would be to do a if check to see if the node already has a distance assigned. [2] https://github.com/Walker-TW/Algorithm-Visualizer/blob/master/src/Algorithms/a*euclidean.js#L22 https://github.com/Walker-TW/Algorithm-Visualizer/blob/maste...