Convert a binary tree into a doubly-linked list in spiral order
Given a binary tree, convert it into a doubly-linked list following the spiral order.
Category: Linked List
Recursively check if the linked list of characters is palindrome or not
Given a linked list of characters, recursively check if it is palindrome or not.
Find a triplet with the given sum in a BST
Given a binary search tree, find a triplet with a given sum present in it.
Merge two BSTs into a doubly-linked list in sorted order
Given two binary search trees, merge them into a doubly-linked list in sorted order.
Construct a height-balanced BST from an unbalanced BST
Given a binary search tree (BST), convert it into a height-balanced binary search tree. For a height-balanced binary search tree, the difference between the height of the left and right subtree of every node is never more than 1.
Remove redundant nodes from a path formed by a linked list
Given a linked list that stores a path formed by cells of a matrix, remove the redundant nodes in that path. The path can be both vertical and horizontal, but never diagonal.
Add a single-digit number to a linked list representing a number
Given a singly linked list whose nodes represent digits of a number, add a single-digit number to it.
Reverse every alternate group of `k` nodes in a linked list
Given a linked list, reverse every alternate group of k nodes where k is a given positive integer.
Add two linked lists without using any extra space
Given a linked list representation of two positive numbers, calculate and store their sum in a new list without extra space.
Determine whether a linked list is palindrome or not
Given a singly linked list of integers, determine if the linked list is a palindrome or not.
Sort a doubly-linked list using merge sort
Given a doubly linked list, sort it using the merge sort algorithm. Merge sort is an efficient sorting algorithm that uses the divide-and-conquer technique to sort a sequence of items.
Convert a ternary tree to a doubly-linked list
Write an efficient algorithm to convert a ternary tree into a doubly-linked list. A ternary tree is a tree data structure in which each node has three child nodes distinguished as left, mid, and right.