Category Leetcode Solutions

Question You are given the root of a binary search tree (BST) and an integer val. Find the node in the BST that the node’s value equals val and return the subtree rooted with that node. If such a node does not exist, return null. Example…

Question You are keeping the scores for a baseball game with strange rules. At the beginning of the game, you start with an empty record. You are given a list of strings operations, where operations[i] is the ith operation you must apply to the record…

Question There is a robot starting at the position (0, 0), the origin, on a 2D plane. Given a sequence of its moves, judge if this robot ends up at (0, 0) after it completes its moves. You are given a string moves that represents the…

Question You are given an integer array nums with no duplicates. A maximum binary tree can be built recursively from nums using the following algorithm: Create a root node whose value is the maximum value in nums. Recursively build the left subtree on the subarray prefix to the left of the…

Question Given the root of a Binary Search Tree and a target number k, return true if there exist two elements in the BST such that their sum is equal to the given target. Example 1: Input: root = [5,3,6,2,4,null,7], k = 9 Output: true…

Question Given the root of a binary tree, return the average value of the nodes on each level in the form of an array. Answers within 10-5 of the actual answer will be accepted. Example 1: Input: root = [3,9,20,null,null,15,7] Output: [3.00000,14.50000,11.00000] Explanation: The average…

Question Table: Salary +————-+———-+ | Column Name | Type | +————-+———-+ | id | int | | name | varchar | | sex | ENUM | | salary | int | +————-+———-+ id is the primary key for this table. The…

Question Table: Cinema +—————-+———-+ | Column Name | Type | +—————-+———-+ | id | int | | movie | varchar | | description | varchar | | rating | float | +—————-+———-+ id is the primary key for this table. Each…

Question Given the root of an n-ary tree, return the postorder traversal of its nodes’ values. Nary-Tree input serialization is represented in their level order traversal. Each group of children is separated by the null value (See examples) Example 1: Input: root =…

Question Table: World +————-+———+ | Column Name | Type | +————-+———+ | name | varchar | | continent | varchar | | area | int | | population | int | | gdp | int | +————-+———+ name is the primary…