What IDA* Solves
IDA* is a classical algorithm for solving shortest-path and state-space search problems with heuristic guidance while using significantly less memory than A*.
Conceptually, it combines the evaluation function f(n) = g(n) + h(n) with iterative deepening. Instead of storing a full frontier in a priority queue, IDA* performs repeated depth-first searches under progressively increasing cost thresholds.
This makes IDA* especially useful in large search spaces where A* becomes impractical due to memory consumption, while still preserving optimality under suitable conditions on the heuristic.