An improved algorithm to reconstruct a binary tree from its inorder and postorder traversals

It is well-known that, given inorder traversal along with one of the preorder or postorder traversals of a binary tree, the tree can be determined uniquely. Several algorithms have been proposed to reconstruct a binary tree from its inorder and preorder traversals. There is one study to reconstruct a binary tree from its inorder and postorder traversals, and this algorithm takes running time of  $ BigO{emph{n}^2} $. In this paper, we present $ proc{InPos} $ an improved algorithm to reconstruct a binary tree from its inorder and postorder traversals. The running time and space complexity of the algorithm are an order of $ BigTheta{emph{n}} $ and $ BigTheta{emph{n}} $ respectively, which we prove to be optimal.