167. Two Sum II - Input Array Is Sorted

Master the efficient Two Pointer technique to solve the sorted Two Sum problem in linear time and constant space.

128. Longest Consecutive Sequence

Master the O(n) solution for finding the longest consecutive sequence in an unsorted array using Hash Sets.

36. Valid Sudoku

Master the art of validating Sudoku boards efficiently using hash sets and fixed-size arrays with O(1) complexity.

238. Product Of Array Except Self

Master the O(n) prefix-suffix pattern to solve LeetCode 238 without division.

347. Top K Frequent Elements

Master LeetCode's Top K Frequent Elements problem with expert insights into optimal O(N) bucket sort, efficient O(N log K) min-heap, and advanced quickselect solutions for finding the most frequent items in an array.

217. Contains Duplicate

Master the fundamental array problem of detecting duplicates using Hash Sets, Sorting, and Brute Force approaches.

3110. Score Of A String

Master string traversal and ASCII manipulation by calculating the score of a string - a perfect introduction to linear algorithms.

49. Group Anagrams

Master the art of grouping anagrams using hash maps and canonical representations to solve LeetCode 49 efficiently.

Binary search

In computer science, binary search, also known as half-interval search,logarithmic search,or binary chop,is a search algorithm that finds the position of a target value within a sorted array.

Inclusion-Exclusion Principle (IEP)

A deep dive into the Inclusion-Exclusion Principle (IEP) in competitive programming with examples of 2-way, 3-way, and 4-way applications.

Bubble Sort

Bubble sort (sometimes called sinking sort) is usually the first sorting algorithm you'll encounter when learning to code. It's simple, easy to wrap your head around, stable, and in-place. The catch? Its quadratic time complexity makes it painfully slow for large datasets.

Depth First Search (DFS)

Depth-first search (DFS) is one of those algorithms you'll see everywhere once you start looking: tree traversals, compilers, maze solvers, dependency resolution, finding Strongly Connected Components (SCCs).