[Solved] You are given the root of a binary tree where each node has a value 0 or 1. Each root-to-leaf path represents a binary number starting with the most significant bit.
[Solved] A valid parentheses string is either empty “”, “(” + A + “)”, or A + B, where A and B are valid parentheses strings, and + represents string concatenation.
[Solved] Given an array of integers preorder, which represents the preorder traversal of a BST (i.e., binary search tree), construct the tree and return its root. It is guaranteed that there is always possible to find a binary search tree with the given requirements for the given test cases.
[Solved] Given a string array words, return an array of all characters that show up in all strings within the words (including duplicates). You may return the answer in any order.
[Solved] In a town, there are n people labeled from 1 to n. There is a rumor that one of these people is secretly the town judge.
[Solved] Given the root of a binary tree with unique values and the values of two different nodes of the tree x and y, return true if the nodes corresponding to the values x and y in the tree are cousins, or false otherwise.
[Solved] Given an integer array nums sorted in non-decreasing order, return an array of the squares of each number sorted in non-decreasing order.
[Solved] A binary tree is uni-valued if every node in the tree has the same value. Given the root of a binary tree, return true if the given tree is uni-valued, or false otherwise.
[Solved] You are given an integer array nums with the following properties: nums.length == 2 * n. nums contains n + 1 unique elements. Exactly one element of nums is repeated n times.