Problem statement（题目原文）Given: What is the result of each of the following statements? Brief idea Know == performs coercion (string → number), === doesn’t; + concatenates when a string is involved; unary + coerces to number. The VOprep team has long accompanied candidates through various major company OAs and VOs, including Microsoft Google, Amazon, Citadel, SIG, providing real-time…

Problem statementImagine you’re working on a language which only supports Stack, but you need a Queue functionality to fulfill the requirement. Design a queue that supports standard operations using stacks. Brief idea (EN)Use two stacks: in and out. The VOprep team has long accompanied candidates through various major company OAs and VOs, including Microsoft Google, Amazon, Citadel,…

Design a simulation for a card game. This game is playable by 2 or more playersand consists of four phases performed in order: shuffle, deal, exchange, and score. Deck of cards: The VOprep team has long accompanied candidates through various major company OAs and VOs, including Microsoft Google, Amazon, Citadel, SIG, providing real-time voice assistance, remote practice,…

Description The 8 Puzzle is a sliding block game played on a 3×3 grid containing 8 numbered tiles (from 1 to 8) and one empty space represented by 0. The objective is to rearrange the tiles into a specific goal configuration by sliding them one at a time.Only tiles adjacent to the empty space (0)…

An integer array “original” is transformed into a doubled array “changed” by appending twice the value of every element in “original”, and then randomly shuffling the resulting array.Given an array “changed”, return “original” if “changed” is a doubled array. If “changed” is not a doubled array, return an empty array. The elements in “original” may…

Given an array nums with n integers, your task is to check if it could become non-decreasing by modifying at most one element.We define an array as non-decreasing if nums[i] <= nums[i+1] holds for every i (0-based) such that 0 <= i <= n-2. English Summary (Approach)Single pass. Count violations where nums[i] > nums[i+1]. If…

Find the unique element in an array where all elements appear twice except one.Examples: Summary (with approach)Use XOR: since a ^ a = 0, a ^ 0 = a, and XOR is associative/commutative, XOR all numbers; the result is the single number. Runs in O(N) time and O(1) space. Alternative: hash counting in O(N) space….

Imagine an array that contains both integers and nested arrays, such as the following:[8, 4, [5, [9], 3], 6].The depth sum is described as the weighted sum of each integer, weighted by their respective depths. In the example, 8’s depth is 1, while 9’s is 3.Given such an array, calculate its depth sum. Examples Summary…

You are given K sorted integer arrays (non-decreasing). Arrays may contain duplicates within the same array and across different arrays.Return a sorted list of unique integers that appear in any of the arrays (i.e., the set union, sorted). Example:A = [-100, -1, -1, 0, 5]B = [0]C = [-1, 0, 0]Output → [-100, -1, 0,…

Given the root of a binary search tree, return a balanced binary search tree that contains the same node values. If there is more than one valid answer, return any of them.A binary search tree is balanced if the depth of the two subtrees of every node never differs by more than 1. Example:Input: root…