Heuristic search

Heuristic search is the family of search algorithms that use problem-specific knowledge to guide exploration, as distinct from blind or exhaustive search methods. The term encompasses informed search, best-first search, A* search, and greedy search, all of which rely on a heuristic function to estimate the desirability of candidate solutions.

The heuristic is the bridge between the general structure of the search algorithm and the specific structure of the problem domain. A well-designed heuristic transforms an intractable search into a tractable one by pruning regions of the space that are unlikely to contain good solutions. The design of heuristics is therefore not merely algorithmic engineering; it is domain modeling.