Count Inversions of an Array

Counting inversions in an array is a fundamental problem in computer science and programming interviews. This guide will explain what array inversions are, the significance of solving this problem, and different approaches to count inversions of an array in Java. What are Inversions in an Array? An inversion in an array is a pair of … Read more

Swap Nodes in Pairs – LeetCode 24 Solution

If you’re a LeetCode enthusiast or just starting out, you might have encountered the problem Swap Nodes in Pairs (LeetCode 24). This is a classic problem that involves swapping adjacent nodes in a linked list. Understanding how to solve this problem is crucial for mastering linked list manipulation and performing well in coding interviews. In … Read more

Find Maximum and minimum of an array using minimum number of comparisons

Introduction for Find Maximum and minimum of an array Finding the maximum and minimum values in an array is a common problem in computer science. While it seems straightforward, optimizing the process to use the least number of comparisons is crucial in scenarios where computational efficiency matters. In this blog, we’ll explore an efficient algorithm … Read more

Merge K Sorted Lists – LeetCode 23 Solution

Merge K Sorted Lists - LeetCode 23 Solution

The LeetCode 23 problem, “Merge K Sorted Lists,” is a classic example that tests your ability to implement optimized algorithms for merging lists. Let’s explore the problem statement, analyze its solutions, and discuss their time and space complexities. Problem Statement for Merge K Sorted Lists You are given an array of k linked lists, where … Read more

Merge Two Sorted Lists | Leetcode 21 Solution

Merge Two Sorted Lists - Leetcode 21 Solution

Introduction The “Merge Two Sorted Lists” problem (Leetcode 21) is a classic algorithmic challenge that tests your understanding of linked lists and pointers. The goal is to merge two sorted linked lists into a single sorted linked list. In this blog post, we will explore multiple solutions to this problem, ranging from a naive approach … Read more

Valid Parentheses | Leetcode 20 Solution

Valid Parentheses - Leetcode 20 Solution

Introduction to Valid Parentheses The “Valid Parentheses” problem (Leetcode 20) is a popular question often asked in coding interviews. The task is to check if a given string containing just the characters ‘(‘, ‘)’, ‘{‘, ‘}’, ‘[‘ and ‘]’ is valid. An input string is valid if the brackets are correctly closed and nested. In … Read more

Remove Nth Node from End of List | Leetcode 19 Solution

Problem Description Given a linked list, remove nth node from end of list and return its head. The list can have various sizes, and the node we need to remove can be anywhere from the beginning to the end of the list. Approach To solve this problem efficiently, we need to think about how to … Read more

4Sum Leetcode | Leetcode 18 Solution

The 4Sum problem is a variation of the classic two-sum problem. The task is to find all unique quadruplets in an array that sum up to a target value. This problem is often encountered in coding interviews and algorithm competitions. In this blog post, we will discuss various solutions for the 4Sum problem, ranging from … Read more

Letter Combinations of a Phone Number | Leetcode 17 Solution

The “Letter Combinations of a Phone Number“ problem is a classic question often asked in technical interviews. It challenges your understanding of backtracking, recursion, and efficient problem-solving. Let’s explore all possible solutions, from a naive approach to an optimized one, with their explanations, complexities, and Java implementations. Problem Statement for Letter Combinations of a Phone … Read more

3Sum Closest | Leetcode 16 Solution

The 3Sum Closest problem from Leetcode is a popular algorithmic challenge that tests your understanding of array manipulation and optimization techniques. In this article, we’ll cover the problem statement, a step-by-step approach to solving it, and explain multiple solutions from naive to optimized with their complexities. We’ll also provide well-commented Java code for each solution. … Read more