It is based on the concept of LIFO. As it stands for Last In First Out. Also, implemented in recursion with LIFO stack data structure. Thus, It used to create the same set of nodes as the Breadth-First method, only in the different order. As the path is been stored in each iteration from root to leaf node. Thus, store nodes are linear with space requirement. With branching factor b and depth as m, the storage space is bm.