Recursive function to construct binary of size n from Inorder traversal in [ ] and Postorder traversal post [ ] . Initial values of inStrt and inEnd should be 0 and n - 1. The function doesn 't do any error checking for cases where inorder and postorder do not form a tree
Node * buildUtil ( int in [ ] , int post [ ] , int inStrt , int inEnd , int * pIndex , unordered_map < int , int > & mp ) {