Imagine you’re working with a system that needs to send lists of strings across a network. Each string may contain special characters, including commas, numbers, or even spaces, which makes it tricky to separate one string from another. The task is to design an encoding algorithm that converts a list…
Copy List With Random Pointer – 138. LeetCode
This problem involves copying a linked list where each node contains: 1. A next pointer pointing to the next node in the sequence. 2. A random pointer pointing to any node in the list, or null. The challenge is to create an identical copy of the list, including the random…
Find Duplicate Number – 287. LeetCode
The LeetCode problem Find Duplicate Number requires identifying a duplicate in an array of n + 1 integers, where each integer is in the range 1 to n. Only one duplicate number is guaranteed, and the problem must be solved without modifying the array, in constant space, and with a…
Insert Delete GetRandom O(1) – 380. LeetCode
The LeetCode problem Insert Delete GetRandom O(1) requires implementing a data structure that supports inserting, deleting, and retrieving random element in constant time. Here’s a detail breakdown: Imagine you have a collection of elements, and you want to perform three key operations: 1. Add a new element. 2. Remove an…
Number of Connected Components in an Undirected Graph – 323. LeetCode
In this problem, you are tasked with finding the number of connected components in an undirected graph. A connected component is a subset of nodes such that every pair of nodes in the subset is connected either directly or indirectly, and no additional nodes outside the subset are connected to…
Check If N and Its Double Exist – 1346. LeetCode
The problem “Check If N and Its Double Exist” asks us to determine if there exists an integer n in the array such that n and 2 \times n are both present in the array. Example: • Input: [10, 2, 5, 3] • Output: true (since n = 5 and …
Graph Valid Tree – 261. LeetCode
Imagine you’re given a set of nodes and edges, and you want to determine if they form a valid tree. A valid tree in graph theory has two key properties. In simple terms, a valid tree is like a family tree: everyone is connected and there are no loops. This…
Unique Paths – 62. LeetCode
The Unique Paths problem asks us to find the number of distinct ways to reach the bottom-right corner of a grid starting from the top-left corner. You can only move right or down at any step. This problem is a great example of combinatorics, recursion, and dynamic programming. Imagine you’re…
Subsets – 78. LeetCode
The Subsets problem is classic combinatorics tasks in which you’re given a list of unique integers, and your goal is to return all possible subsets of the list (including the empty subset of the list itself). It’s a fundamental problem that helps build a deeper understanding of recursion, backtracking, and…
Construct Quad Tree – 427. LeetCode
A Quad Tree is a tree data structure used to partition a 2D space into smaller regions for efficient representation and computation. In this problem, we are given a binary matrix and need to construct a Quad Tree where each node represents a region of the matrix. If all values…
