Given the root of a binary tree, return the level order traversal of its nodes’ values. (i.e., from left to right, level by level). Example 1:Input: root = [3,9,20,null,null,15,7]Output: [[3],[9,

Given the root of a binary tree, return the postorder traversal of its nodes’ values. Example 1:Input: root = [1,null,2,3]Output: [3,2,1] Example 2:Input: root = []Output: [] Example 3:Input

Given the root of a binary tree, return the inorder traversal of its nodes’ values. Example 1:Input: root = [1,null,2,3]Output: [1,3,2] Example 2:Input: root = []Output: [] Example 3:Input:

Given the root of a binary tree, invert the tree, and return its root. Example 1:Input: root = [4,2,7,1,3,6,9]Output: [4,7,2,9,6,3,1] Example 2:Input: root = [2,1,3]Output: [2,3,1] Example 3

Given the roots of two binary trees p and q, write a function to check if they are the same or not. Two binary trees are considered the same if they are structurally identical, and the nodes have the

Given the root of a binary tree, return its maximum depth. A binary tree’s maximum depth is the number of nodes along the longest path from the root node down to the farthest leaf node. Example 1:Inpu

Given the root of a binary tree, return the preorder traversal of its nodes’ values. Example 1:Input: root = [1,null,2,3]Output: [1,2,3] Example 2:Input: root = []Output: [] Example 3:Input:

Given a string s consisting of words and spaces, return the length of the last word in the string. A word is a maximal substring consisting of non-space characters only. Example 1:Input: s = “Hel

You are given the head of a singly linked-list. The list can be represented as:L0 → L1 → … → Ln - 1 → Ln Reorder the list to be on the following form:L0 → Ln → L1 → Ln - 1 → L2 → Ln - 2 → …You may not

You are given the heads of two sorted linked lists list1 and list2. Merge the two lists into one sorted list. The list should be made by splicing together the nodes of the first two lists. Return the