Minimize f(n)=g(n)+h(n) combines the advantage of uniform cost search + greedy search A* is complete, optimal. Its space complexity is still prohibitive. Iterative improvement algorithms keep only a single state in memory, but can get stuck on local maxima. In this algorithm each iteration is a dfs just as in regular iterative deepening. The depth first search is modified to use an f-cost limit rather than a depth limit. Thus each iteration expands all nodes inside the contour for the current f-cost.