Learn Algorithms
Visually

Sort an array by repeatedly swapping adjacent elements that are in the wrong order

Selection Sort

Sort an array by repeatedly finding the minimum element and placing it at the beginning

Insertion Sort

Build a sorted portion by inserting each element into its correct position one at a time

Iterative Merge Sort

Sort an array using bottom-up merge operations without recursion

Heap Sort

Sort an array by building a max heap and repeatedly placing the largest element at the end

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Array

Array manipulation techniques — rotating, searching, and rearranging elements efficiently

Rotate Array

MediumVery Important

Rotate an array to the right by k steps using the efficient reversal algorithm.

Two Pointers

Move Zeros

EasyVery Important

Move all zeros to the end while preserving the relative order of non-zero elements.

Two Pointers

Remove Duplicates from Sorted Array

Remove duplicates from a sorted array in-place so each unique element appears once.

Two Pointers

Two Sum

Find two indices in the array such that their values add up to a given target using an efficient hash map approach.

Searching & Indexing

Best Time to Buy and Sell Stock

Prefix, Product & Accumulators

Find the maximum profit by choosing one day to buy and a later day to sell.

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Linked List

Operations on linked data structures — traversal, reversal, and merging

Reverse Linked List

Reverse a singly linked list by changing the direction of pointers iteratively

Tree

Hierarchical data structure operations — traversal, search, and balancing

Binary Search Tree Search

Search for a value in a BST by comparing and traversing left or right at each node

Graph

Graph traversal and shortest path algorithms — BFS, DFS, and more

Breadth-First Search

Traverse a graph level by level using a queue, visiting all neighbors before moving deeper

Stack & Queue

LIFO and FIFO data structure operations and applications

Valid Parentheses

Check if a string of brackets is valid using a stack to match opening and closing pairs

Dynamic Programming

Solving complex problems by breaking them into overlapping subproblems

Fibonacci (Dynamic Programming)

Compute the Nth Fibonacci number efficiently using bottom-up dynamic programming

String

String manipulation and pattern matching algorithms

Reverse String

Reverse a string in-place using the two-pointer technique, swapping characters from both ends

Longest Common Prefix

Find the longest common prefix among all strings.

Roman to Integer

Convert a Roman numeral string into its integer value.

Isomorphic Strings

Check whether two strings can be transformed using a one-to-one character mapping.

Encode and Decode Strings

Encode a list of strings into one string and decode it back safely.