## Find preorder traversal of a binary tree from its inorder and postorder sequence

Write an efficient algorithm to find preorder traversal of a binary tree from its inorder and postorder sequence without constructing the tree.

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Write an efficient algorithm to find preorder traversal of a binary tree from its inorder and postorder sequence without constructing the tree.

Find all N-digit numbers with equal sum of digits at even and odd index. N varies from [1 to 9].

Design a stack to support an additional operation which returns the minimum element from the stack in constant time. The stack should continue supporting all other operations like push, pop, top, size, empty, etc, with no degrade in performance for these operations.

Given a multilevel linked list, convert it into a singly linked list in such a way that all nodes of first level appears first, followed by all nodes of second level, and so on. The multilevel linked list is similar to the simple linked list except that it has one extra field which points to …

Given an array of integers, rearrange the array such that it contains positive and negative numbers at alternate positions. If array contains more positive or negative elements, they should be moved to end of the array.

Calculate total number of ways to achieve given sum with n throws of dice having k faces.

Given a binary search tree, modify it such that every key is updated to contain sum of all greater keys present in BST.

Given a weighted digraph (Directed Graph), find the least cost path from given source to destination that have exactly m edges.

Given a string, find first non-repeating character in it by doing only one traversal of it.

Given a binary tree that is only one swap away from becoming a BST, convert the binary tree into BST in single traversal of it.

Given a binary tree, write an efficient algorithm to find maximum sum path between any two leaves in it.

Given a binary M x N row-wise sorted matrix, find a row which contains maximum number of 1 in linear time.