Link to problem Description Given a string s which represents an expression, evaluate this expression and return its value. The integer division should truncate toward zero. You may assume that...

Link to problem Description You are given the root of a binary tree containing digits from 0 to 9 only. Each root-to-leaf path in the tree represents a number. For example, the root-to-leaf ...

Link to problem Description Implement a SnapshotArray that supports the following interface: SnapshotArray(int length) initializes an array-like data structure with the given length. Initiall...

Link to problem Description You are given an integer array ranks representing the ranks of some mechanics. ranks$_\text{i}$ is the rank of the i$^\text{th}$ mechanic. A mechanic with a rank r can...

Link to problem Description You are given a 0-indexed integer array nums representing the initial positions of some marbles. You are also given two 0-indexed integer arrays moveFrom and moveTo of...

Link to problem Description Given a 0-indexed integer array nums, return the number of distinct quadruplets (a, b, c, d) such that: nums[a] + nums[b] + nums[c] == nums[d], and a < b <...

Link to problem Description Given the root of a binary tree, return the number of nodes where the value of the node is equal to the average of the values in its subtree. Note: The average of ...

Link to problem Description You are given an array prices where prices[i] is the price of a given stock on the ith day. You want to maximize your profit by choosing a single day to buy one stock...

Link to problem Description You are given an array prices where prices[i] is the price of a given stock on the ith day. Find the maximum profit you can achieve. You may complete at most two tran...

Link to problem Problem You are given two integer arrays nums1 and nums2. You are tasked to implement a data structure that supports queries of two types: Add a positive integer to an element...