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.
Given the head of a singly linked list where elements are sorted in ascending order, convert it into a height-balanced binary search tree. A height-balanced binary search tree is one where the depth of the two subtrees of every node never differs by more than 1.
Given an array nums of size n, return the majority element. The majority element is the element that appears more than n // 2 times. You may assume that the majority element always exists in the array.
