You are given an array of strings. Group the strings that are anagrams of each other together and return them as a list of lists. An anagram is a word or phrase formed by rearranging the letters of another word or phrase.
You are given an m x n matrix of integers. Whenever an element in the matrix is 0, you need to set all elements in the corresponding row and column to 0, but the operation must be done in place. This means you cannot use extra space for another matrix.
Given two integer arrays, preorder and inorder, representing the preorder and inorder traversals of a binary tree, your task is to reconstruct and return the binary tree. The values in the arrays are unique, and the preorder traversal provides the sequence in which nodes are visited before their children, while the inorder traversal provides the order in which nodes are visited between their children.
You are given a reference to a node in a connected, undirected graph. Each node in the graph contains a value (integer) and a list of its neighbors. Your task is to return a deep copy of the entire graph starting from the given node.
Given a linked list where each node contains a value, a next pointer, and a random pointer (which can point to any node in the list or be null), create a deep copy of the list. The deep copy should consist of exactly n new nodes where each node has its value set to the value of its corresponding original node, and the next and random pointers of the new nodes should represent the same list state as the original. None of the pointers in the new list should point to nodes in the original list.
