Dmitrii Volyx

Implement a basic calculator to evaluate a simple expression string. The expression string contains only non-negative integers, ‘+’, ‘-’, ‘*’, ‘/’ operators, and open ‘(’ and closing parentheses ‘)’. The integer division should truncate toward zero. You may assume that the given expression is always valid. All intermediate results will be in the range of [-231, 231 - 1]. Note: You are not allowed to use any built-in function which evaluates strings as mathematical expressions, such as eval(). ...

You are given an array of points in the X-Y plane points where points[i] = [xi, yi]. Return the minimum area of a rectangle formed from these points, with sides parallel to the X and Y axes. If there is not any such rectangle, return 0. Example 1: Input: points = [[1,1],[1,3],[3,1],[3,3],[2,2]] Output: 4 Example 2: Input: points = [[1,1],[1,3],[3,1],[3,3],[4,1],[4,3]] Output: 2 Constraints: ...

You are given a string expression representing a Lisp-like expression to return the integer value of. The syntax for these expressions is given as follows. -An expression is either an integer, let expression, add expression, mult expression, or an assigned variable. Expressions always evaluate to a single integer. (An integer could be positive or negative.) A let expression takes the form “(let v1 e1 v2 e2 … vn en expr)”, where let is always the string “let”, then there are one or more pairs of alternating variables and expressions, meaning that the first variable v1 is assigned the value of the expression e1, the second variable v2 is assigned the value of the expression e2, and so on sequentially; and then the value of this let expression is the value of the expression expr. An add expression takes the form “(add e1 e2)” where add is always the string “add”, there are always two expressions e1, e2 and the result is the addition of the evaluation of e1 and the evaluation of e2. A mult expression takes the form “(mult e1 e2)” where mult is always the string “mult”, there are always two expressions e1, e2 and the result is the multiplication of the evaluation of e1 and the evaluation of e2. For this question, we will use a smaller subset of variable names. A variable starts with a lowercase letter, then zero or more lowercase letters or digits. Additionally, for your convenience, the names “add”, “let”, and “mult” are protected and will never be used as variable names. Finally, there is the concept of scope. When an expression of a variable name is evaluated, within the context of that evaluation, the innermost scope (in terms of parentheses) is checked first for the value of that variable, and then outer scopes are checked sequentially. It is guaranteed that every expression is legal. Please see the examples for more details on the scope. Example 1: Input: expression = "(let x 2 (mult x (let x 3 y 4 (add x y))))" Output: 14 Explanation: In the expression (add x y), when checking for the value of the variable x, we check from the innermost scope to the outermost in the context of the variable we are trying to evaluate. Since x = 3 is found first, the value of x is 3. Example 2: Input: expression = "(let x 3 x 2 x)" Output: 2 Explanation: Assignment in let statements is processed sequentially. Example 3: Input: expression = "(let x 1 y 2 x (add x y) (add x y))" Output: 5 Explanation: The first (add x y) evaluates as 3, and is assigned to x. The second (add x y) evaluates as 3+2 = 5. Example 4: Input: expression = "(let x 2 (add (let x 3 (let x 4 x)) x))" Output: 6 Explanation: Even though (let x 4 x) has a deeper scope, it is outside the context of the final x in the add-expression. That final x will equal 2. Example 5: Input: expression = "(let a1 3 b2 (add a1 1) b2)" Output: 4 Explanation: Variable names can contain digits after the first character. Constraints: ...

Given an array of strings words (without duplicates), return all the concatenated words in the given list of words. A concatenated word is defined as a string that is comprised entirely of at least two shorter words in the given array. Example 1: Input: words = ["cat","cats","catsdogcats","dog","dogcatsdog","hippopotamuses","rat","ratcatdogcat"] Output: ["catsdogcats","dogcatsdog","ratcatdogcat"] Explanation: "catsdogcats" can be concatenated by "cats", "dog" and "cats"; "dogcatsdog" can be concatenated by "dog", "cats" and "dog"; "ratcatdogcat" can be concatenated by "rat", "cat", "dog" and "cat". Example 2: Input: words = ["cat","dog","catdog"] Output: ["catdog"] Constraints: ...

There are several cards arranged in a row, and each card has an associated number of points. The points are given in the integer array cardPoints. In one step, you can take one card from the beginning or from the end of the row. You have to take exactly k cards. Your score is the sum of the points of the cards you have taken. ...

You are given an integer n, which indicates that there are n courses labeled from 1 to n. You are also given an array relations where relations[i] = [prevCoursei, nextCoursei], representing a prerequisite relationship between course prevCoursei and course nextCoursei: course prevCoursei has to be taken before course nextCoursei. In one semester, you can take any number of courses as long as you have taken all the prerequisites in the previous semester for the courses you are taking. ...

Given a n * n matrix grid of 0’s and 1’s only. We want to represent the grid with a Quad-Tree. Return the root of the Quad-Tree representing the grid. Notice that you can assign the value of a node to True or False when isLeaf is False, and both are accepted in the answer. A Quad-Tree is a tree data structure in which each internal node has exactly four children. Besides, each node has two attributes: ...

You are given an n x n 2D matrix representing an image, rotate the image by 90 degrees (clockwise). You have to rotate the image in-place, which means you have to modify the input 2D matrix directly. DO NOT allocate another 2D matrix and do the rotation. Example 1: Input: matrix = [[1,2,3],[4,5,6],[7,8,9]] Output: [[7,4,1],[8,5,2],[9,6,3]] Example 2: Input: matrix = [[5,1,9,11],[2,4,8,10],[13,3,6,7],[15,14,12,16]] Output: [[15,13,2,5],[14,3,4,1],[12,6,8,9],[16,7,10,11]] Example 3: Input: matrix = [[1]] Output: [[1]] Example 4: Input: matrix = [[1,2],[3,4]] Output: [[3,1],[4,2]] Constraints: ...

You are given a list of airline tickets where tickets[i] = [fromi, toi] represent the departure and the arrival airports of one flight. Reconstruct the itinerary in order and return it. All of the tickets belong to a man who departs from “JFK”, thus, the itinerary must begin with “JFK”. If there are multiple valid itineraries, you should return the itinerary that has the smallest lexical order when read as a single string. ...

Given the root of a binary tree, construct a 0-indexed m x n string matrix res that represents a formatted layout of the tree. The formatted layout matrix should be constructed using the following rules: The height of the tree is height and the number of rows m should be equal to height + 1. The number of columns n should be equal to 2height+1 - 1. Place the root node in the middle of the top row (more formally, at location res[0][(n-1)/2]). For each node that has been placed in the matrix at position res[r][c], place its left child at res[r+1][c-2height-r-1] and its right child at res[r+1][c+2height-r-1]. Continue this process until all the nodes in the tree have been placed. Any empty cells should contain the empty string “”. Return the constructed matrix res. ...