#### 430. Flatten a Multilevel Doubly Linked List

You are given a doubly linked list, which contains nodes that have a next pointer, a previous pointer, and an additional child pointer. This child pointer may or may not point to a separate doubly linked list, also containing these special nodes. These child lists may have one or more children of their own, and […]

#### Typescript Data Structures: Linked List

In the vast expanse of data structures available to developers, the LinkedList holds a unique place. Known for its efficiency in insertion and deletion operations, it’s a staple in algorithm design and application development. This post explores how to implement a LinkedList in TypeScript, bringing together the efficiency of this data structure with the strong […]

#### 448. Find All Numbers Disappeared in an Array

Given an array nums of n integers where nums[i] is in the range [1, n], return an array of all the integers in the range [1, n] that do not appear in nums. Example 1: Input: nums = [4,3,2,7,8,2,3,1] Output: [5,6] Example 2: Input: nums = [1,1] Output: [2] Constraints: n == nums.length 1 <= […]

#### 414. Third Maximum Number

Given an integer array nums, return the third distinct maximum number in this array. If the third maximum does not exist, return the maximum number. Example 1: Input: nums = [3,2,1] Output: 1 Explanation: The first distinct maximum is 3. The second distinct maximum is 2. The third distinct maximum is 1. Example 2: Input: […]

#### 487. Max Consecutive Ones II

Given a binary array nums, return the maximum number of consecutive 1‘s in the array if you can flip at most one 0. Example 1: Input: nums = [1,0,1,1,0] Output: 4 Explanation: – If we flip the first zero, nums becomes [1,1,1,1,0] and we have 4 consecutive ones. – If we flip the second zero, […]

#### 905. Sort Array By Parity

Given an integer array nums, move all the even integers at the beginning of the array followed by all the odd integers. Return any array that satisfies this condition. Example 1: Input: nums = [3,1,2,4] Output: [2,4,3,1] Explanation: The outputs [4,2,3,1], [2,4,1,3], and [4,2,1,3] would also be accepted. Example 2: Input: nums = [0] Output: […]

#### Check If N and Its Double Exist

Given an array arr of integers, check if there exist two indices i and j such that: i != j 0 <= i, j < arr.length arr[i] == 2 * arr[j] Example 1: Input: arr = [10,2,5,3] Output: true Explanation: For i = 0 and j = 2, arr[i] == 10 == 2 * 5 […]