Who Should Take This Course?

Understanding Data Structures

Types of Data Structures

An Overview of Big-O

Introduction to Arrays

Arrays in Different Programming Languages

Problem 1: Running Sum of 1d Array (easy)

Solution: Running Sum of 1d Array (easy)

Problem 2: Contains Duplicate (easy)

Solution: Contains Duplicate

Problem 3: Left and Right Sum Differences (easy)

Solution: Left and Right Sum Differences (easy)

Problem 4: Find the Highest Altitude (easy)

Solution: Find the Highest Altitude (easy)

Introduction to Matrix

Problem 1: Richest Customer Wealth (easy)

Solution: Richest Customer Wealth (easy)

Problem 2: Matrix Diagonal Sum (easy)

Solution: Matrix Diagonal Sum (easy)

Problem 3: Row With Maximum Ones(easy)

Solution: Row With Maximum Ones(easy)

Introduction to Stack

Implementing Stack Data Structure

Using Built-in Stack in Different Programming Languages

Applications of Stack

Problem 1: Balanced Parentheses (easy)

Solution: Balanced Parentheses

Problem 2: Reverse a String (easy)

Solution: Reverse a String

Problem 3: Decimal to Binary Conversion (medium)

Solution: Decimal to Binary Conversion

Problem 4: Next Greater Element (easy)

Solution: Next Greater Element

Problem 5: Sorting a Stack (easy)

Solution: Sorting a Stack

Problem 6: Simplify Path (medium)

Solution: Simplify Path

Problem 7: Remove All Adjacent Duplicates In String (medium)

Solution: Remove All Adjacent Duplicates In String

Problem 8: Removing Stars From a String (medium)

Solution: Removing Stars From a String

Problem 9: Make The String Great (easy)

Solution: Make The String Great

Introduction to Queues

Working with Simple Queues

Queue Implementation in Different Languages

Types of Queue

Diving Deeper – Circular Queues and Deques

Applications and Advanced Concepts

Reverse a Queue (easy)

Solution: Reverse a Queue

Implement Stack using Queues (easy)

Solution: Implement Stack using Queues

Generate Binary Numbers from 1 to N

Solution: Generate Binary Numbers from 1 to N

Zigzag Iterator (medium)

Solution: Zigzag Iterator

Max of All Subarrays of Size 'k' (medium)

Solution: Max of All Subarrays of Size 'k'

Palindrome Check using Queue (easy)

Solution: Palindrome Check using Queue

Introduction to LinkedList

Types of LinkedList

Operations on Singly Linked List

Operations on Doubly Linked List

Problem 1: Reverse Linked List (easy)

Solution: Reverse Linked List

Problem 2: Remove Duplicates from Sorted List (easy)

Solution: Remove Duplicates from Sorted List

Problem 3: Merge Two Sorted Lists (easy)

Solution: Merge Two Sorted Lists

Problem 4: Find if Doubly Linked List is a Palindrome (easy)

Solution: Find if Doubly Linked List is a Palindrome

Problem 5: Swap Nodes in Pairs (medium)

Solution: Swap Nodes in Pairs

Introduction to Tree

Types of Tree

BST Traversal Techniques

BST Operations

Maximum Depth (or Height) of Binary Tree (easy)

Solution: Maximum Depth (or Height) of Binary Tree

Balanced Binary Tree (easy)

Solution: Balanced Binary Tree

Minimum Difference Between BST Nodes (easy)

Solution: Minimum Difference Between BST Nodes

Range Sum of BST (easy)

Solution: Range Sum of BST

Kth Smallest Element in a BST (medium)

Solution: Kth Smallest Element in a BST

Closest Binary Search Tree Value (medium)

Solution: Closest Binary Search Tree Value

Merge Two Binary Trees (medium)

Solution: Merge Two Binary Trees

Introduction to Hash Tables

Hashing, Collisions, Overflow, and Resizing in Hashtables

Using Hashtable in Different Programming Languages

Problem 1: First Non-repeating Character (easy)

Solution: First Non-repeating Character (easy)

Problem 2: Largest Unique Number (easy)

Solution: Largest Unique Number (easy)

Problem 3: Maximum Number of Balloons (easy)

Solution: Maximum Number of Balloons (easy)

Problem 4: Longest Palindrome(easy)

Solution: Longest Palindrome(easy)

Problem 5: Ransom Note (easy)

Solution: Ransom Note (easy)

Introduction to HashSets

Using HashSets in Different Programming Languages

Problem 1: Counting Elements (easy)

Solution: Counting Elements (easy)

Problem 2: Jewels and Stones (easy)

Solution: Jewels and Stones (easy)

Problem 3: Unique Number of Occurrences (easy)

Solution: Unique Number of Occurrences (easy)

Problem 4: Longest Substring Without Repeating Characters (medium)

Solution: Longest Substring Without Repeating Characters (medium)

Introduction to Heap

Heap Operations

Take Gifts From the Richest Pile(easy)

Solution: Take Gifts From the Richest Pile(easy)

Sort Characters By Frequency (easy)

Solution: Sort Characters By Frequency (easy)

Minimum Cost to Connect Sticks(medium)

Solution: Minimum Cost to Connect Sticks(medium)

Find the Median of a Number Stream (medium)

Solution: Find the Median of a Number Stream

Introduction to Graph

Types of Graph

Graph Representations

Graph Traversal - Depth First Search(DFS)

Graph Traversal - Breadth First Search (BFS)

Find if Path Exists in Graph(easy)

Solution: Find if Path Exists in Graph(easy)

Number of Provinces (medium)

Solution: Number of Provinces

Find Eventual Safe States (medium)

Solution: Find Eventual Safe States

Minimum Number of Vertices to Reach All Nodes(medium)

Solution: Minimum Number of Vertices to Reach All Nodes(medium)

Bus Routes (hard)

Solution: Bus Routes

Introduction to Trie

Implement Trie (Prefix Tree) (medium)

Solution: Implement Trie (Prefix Tree)

Index Pairs of a String (easy)

Solution: Index Pairs of a String

Extra Characters in a String (medium)

Solution: Extra Characters in a String

Search Suggestions System (medium)

Solution: Search Suggestions System

Design Add and Search Words Data Structure (medium)

Solution: Design Add and Search Words Data Structure

Introduction to Sorting Algorithms

Advanced Sorting Techniques

Apple Redistribution into Boxes (easy)

Solution: Apple Redistribution into Boxes

Sort Array by Increasing Frequency (easy)

Solution: Sort Array by Increasing Frequency

Sort Vowels in a String (medium)

Solution: Sort Vowels in a String

Reduction Operations to Make the Array Elements Equal (medium)

Solution: Reduction Operations to Make the Array Elements Equal

Divide Array Into Arrays With Max Difference (medium)

Solution: Divide Array Into Arrays With Max Difference

Top 'K' Frequent Numbers (medium)

Solution: Top 'K' Frequent Numbers

Meeting Rooms II (medium)

Solution: Meeting Rooms II

Introduction to Searching Algorithms

Maximum Count of Positive Integer and Negative Integer (easy)

Solution: Maximum Count of Positive Integer and Negative Integer

Minimum Common Value (easy)

Solution: Minimum Common Value

Frequency of the Most Frequent Element (medium)

Solution: Frequency of the Most Frequent Element

Minimize the Maximum of Two Arrays (medium)

Solution: Minimize the Maximum of Two Arrays

Search a 2D Matrix II (medium)

Solution: Search a 2D Matrix II

Sqrt (medium)

Solution: Sqrt

Introduction to Greedy Algorithm

Valid Palindrome II (easy)

Solution: Valid Palindrome II

Maximum Length of Pair Chain (medium)

Solution: Maximum Length of Pair Chain

Minimum Add to Make Parentheses Valid (medium)

Solution: Minimum Add to Make Parentheses Valid

Remove Duplicate Letters (medium)

Solution: Remove Duplicate Letters

Largest Palindromic Number (Medium)

Solution: Largest Palindromic Number

Removing Minimum and Maximum From Array (medium)

Solution: Removing Minimum and Maximum From Array

Introduction to Divide and Conquer Algorithm

Longest Nice Substring (easy)

Solution: Longest Nice Substring

Majority Element (easy)

Solution: Majority Element

Sort List (medium)

Solution: Sort List

Maximum Binary Tree (medium)

Solution: Maximum Binary Tree

Beautiful Array (medium)

Solution: Beautiful Array

Grokking the Art of Recursive Problem-Solving

Demystifying Recursion

Recursion Types

Recursion vs. Iteration

Recursive Algorithm Strategies

Complexity Analysis

1. Basic Sum

Solution: Basic Sum

2. Factorial

Solution: Factorial

3. Greatest Common Divisor (GCD)

Solution: Greatest Common Divisor (GCD)

4. Converting Decimal to Binary

Solution: Converting Decimal to Binary

5. Check Prime

Solution: Check Prime

6. Perfect Square

Solution: Perfect Square

7. Number Frequency

Solution: Number Frequency

8. Pascal's Triangle

Solution: Pascal's Triangle

9. Binary Search

Solution: Binary Search

10. Inserting a new node in a BST

Solution: Inserting a new node in a BST

11. BST Inorder Traversal

Solution: BST Inorder Traversal

12. Merge Sort

Solution: Merge Sort

13. Quick Sort

Solution: Quick Sort

14. Depth First Search

Solution: Depth First Search

15. Removing Nodes From Linked List

Solution: Removing Nodes From Linked List

16. Fibonacci Series Using Memoization

Solution: Fibonacci Series Using Memoization

17. Good Number

Solution: Good Number

18. Split BST

Solution: Split BST

19. Pow(x,n)

Solution: Pow(x,n)

Who Should Take This Course?

Course Overview

Why warmup?

Contains Duplicate (easy)

Solution: Contains Duplicate

Pangram (easy)

Solution: Pangram

Reverse Vowels (easy)

Solution: Reverse Vowels

Valid Palindrome (easy)

Solution: Valid Palindrome

Valid Anagram (easy)

Solution: Valid Anagram

Shortest Word Distance (easy)

Solution: Shortest Word Distance

Number of Good Pairs (easy)

Solution: Number of Good Pairs

Sqrt (medium)

Solution: Sqrt

Introduction to Two Pointers Pattern

Pair with Target Sum (easy)

Solution: Pair with Target Sum

Find Non-Duplicate Number Instances (easy)

Solution: Find Non-Duplicate Number Instances

Squaring a Sorted Array (easy)

Solution: Squaring a Sorted Array

Triplet Sum to Zero (medium)

Solution: Triplet Sum to Zero

Triplet Sum Close to Target (medium)

Solution: Triplet Sum Close to Target

Triplets with Smaller Sum (medium)

Solution: Triplets with Smaller Sum

Dutch National Flag Problem (medium)

Solution: Dutch National Flag Problem

Problem Challenge 1: Quadruple Sum to Target (medium)

Solution: Problem Challenge 1: Quadruple Sum to Target

Problem Challenge 2: Comparing Strings containing Backspaces (medium)

Solution: Problem Challenge 2: Comparing Strings containing Backspaces

Problem Challenge 3: Minimum Window Sort (medium)

Solution: Problem Challenge 3: Minimum Window Sort

Introduction to Fast & Slow Pointers Pattern

LinkedList Cycle (easy)

Solution: LinkedList Cycle

Middle of the LinkedList (easy)

Solution: Middle of the LinkedList

Start of LinkedList Cycle (medium)

Solution: Start of LinkedList Cycle

Happy Number (medium)

Solution: Happy Number

Problem Challenge 1: Palindrome LinkedList (medium)

Solution: Problem Challenge 1: Palindrome LinkedList

Problem Challenge 2: Rearrange a LinkedList (medium)

Solution: Problem Challenge 2: Rearrange a LinkedList

Problem Challenge 3: Cycle in a Circular Array (hard)

Solution: Problem Challenge 3: Cycle in a Circular Array

Introduction to Sliding Window Pattern

Maximum Sum Subarray of Size K (easy)

Solution: Maximum Sum Subarray of Size K

Smallest Subarray With a Greater Sum (easy)

Solution: Smallest Subarray With a Greater Sum

Longest Substring with K Distinct Characters (medium)

Solution: Longest Substring with K Distinct Characters

Fruits into Baskets (medium)

Solution: Fruits into Baskets

Longest Substring with Same Letters after Replacement (hard)

Solution: Longest Substring with Same Letters after Replacement

Longest Subarray with Ones after Replacement (hard)

Solution: Longest Subarray with Ones after Replacement

Problem Challenge 1: Permutation in a String (hard)

Solution: Problem Challenge 1: Permutation in a String

Problem Challenge 2: String Anagrams (hard)

Solution: Problem Challenge 2: String Anagrams

Problem Challenge 3: Smallest Window containing Substring (hard)

Solution: Problem Challenge 3: Smallest Window containing Substring

Problem Challenge 4: Words Concatenation (hard)

Solution: Problem Challenge 4: Words Concatenation

Problem Challenge 5: Counting Subarrays with Product Less than a Target (hard)

Solution Problem Challenge 5: Counting Subarrays with Product Less than a Target

Problem Challenge 6: Subarrays with Product Less than a Target (hard)

Solution Problem Challenge 5: : Subarrays with Product Less than a Target

Introduction to Merge Intervals Pattern

Merge Intervals (medium)

Solution: Merge Intervals

Insert Interval (medium)

Solution: Insert Interval

Intervals Intersection (medium)

Solution: Intervals Intersection

Conflicting Appointments (medium)

Solution: Conflicting Appointments

Problem Challenge 1: Minimum Meeting Rooms (hard)

Solution: Problem Challenge 1: Minimum Meeting Rooms

Problem Challenge 2: Maximum CPU Load (hard)

Solution: Problem Challenge 2: Maximum CPU Load

Problem Challenge 3: Employee Free Time (hard)

Solution: Problem Challenge 3: Employee Free Time

Introduction to Cyclic Sort Pattern

Cyclic Sort (easy)

Solution: Cyclic Sort

Find the Missing Number (easy)

Solution: Find the Missing Number

Find all Missing Numbers (easy)

Solution: Find all Missing Numbers

Find the Duplicate Number (easy)

Solution: Find the Duplicate Number

Find all Duplicate Numbers (easy)

Solution: Find all Duplicate Numbers

Problem Challenge 1: Find the Corrupt Pair (easy)

Solution: Problem Challenge 1: Find the Corrupt Pair

Problem Challenge 2: Find the Smallest Missing Positive Number (medium)

Solution: Problem Challenge 2: Find the Smallest Missing Positive Number

Problem Challenge 3: Find the First K Missing Positive Numbers (hard)

Solution: Problem Challenge 3: Find the First K Missing Positive Numbers

Introduction to In-place Reversal of a Linked List Pattern

Reverse a LinkedList (easy)

Solution: Reverse a LinkedList

Reverse a Sub-list (medium)

Solution: Reverse a Sub-list

Reverse every K-element Sub-list (medium)

Solution: Reverse every K-element Sub-list

Problem Challenge 1: Reverse alternating K-element Sub-list (medium)

Solution: Problem Challenge 1: Reverse alternating K-element Sub-list

Problem Challenge 2: Rotate a LinkedList (medium)

Solution: Problem Challenge 2: Rotate a LinkedList

Introduction to Stack

Implementing Stack Data Structure

Using Built-in Stack in Different Programming Languages

Applications of Stack

Problem 1: Balanced Parentheses (easy)

Solution: Balanced Parentheses

Problem 2: Reverse a String (easy)

Solution: Reverse a String

Problem 3: Decimal to Binary Conversion (medium)

Solution: Decimal to Binary Conversion

Problem 4: Next Greater Element (easy)

Solution: Next Greater Element

Problem 5: Sorting a Stack (easy)

Solution: Sorting a Stack

Problem 6: Simplify Path (medium)

Solution: Simplify Path

Introduction to Monotonic Stack

Remove Nodes From Linked List (easy)

Solution: Remove Nodes From Linked List

Remove All Adjacent Duplicates In String (easy)

Solution: Remove All Adjacent Duplicates In String

Next Greater Element (easy)

Solution: Next Greater Element

Daily Temperatures (easy)

Solution: Daily Temperatures

Remove All Adjacent Duplicates in String II (medium)

Solution: Remove All Adjacent Duplicates in String II

Sum of Subarray Minimums (medium)

Solution: Sum of Subarray Minimums

Remove K Digits (hard)

Solution: Remove K Digits

Introduction to Hash Tables

Hashing, Collisions, Overflow, and Resizing in Hashtables

Using Hashtable in Different Programming Languages

Problem 1: First Non-repeating Character (easy)

Solution: First Non-repeating Character (easy)

Problem 2: Largest Unique Number (easy)

Solution: Largest Unique Number (easy)

Problem 3: Maximum Number of Balloons (easy)

Solution: Maximum Number of Balloons (easy)

Problem 4: Longest Palindrome(easy)

Solution: Longest Palindrome(easy)

Problem 5: Ransom Note (easy)

Solution: Ransom Note (easy)

Introduction to Level Order Traversal Pattern

Reverse Level Order Traversal (easy)

Solution: Reverse Level Order Traversal

Find Largest Value in Each Tree Row (medium)

Solution: Find Largest Value in Each Tree Row

Maximum Width of Binary Tree (medium)

Solution: Maximum Width of Binary Tree

Maximum Level Sum of a Binary Tree (medium)

Solution: Maximum Level Sum of a Binary Tree

Zigzag Traversal (medium)

Solution: Zigzag Traversal

Even Odd Tree (medium)

Solution: Even Odd Tree

N-ary Tree Level Order Traversal (hard)

Solution: N-ary Tree Level Order Traversal

Introduction to Tree Breadth First Search Pattern

Binary Tree Level Order Traversal (easy)

Solution: Binary Tree Level Order Traversal

Reverse Level Order Traversal (easy)

Solution: Reverse Level Order Traversal

Zigzag Traversal (medium)

Solution: Zigzag Traversal

Level Averages in a Binary Tree (easy)

Solution: Level Averages in a Binary Tree

Minimum Depth of a Binary Tree (easy)

Solution: Minimum Depth of a Binary Tree

Level Order Successor (easy)

Solution: Level Order Successor

Connect Level Order Siblings (medium)

Solution: Connect Level Order Siblings

Problem Challenge 1: Connect All Level Order Siblings (medium)

Solution: Problem Challenge 1: Connect All Level Order Siblings

Problem Challenge 2: Right View of a Binary Tree (easy)

Solution: Problem Challenge 2: Right View of a Binary Tree

Introduction to Tree Depth First Search Pattern

Binary Tree Path Sum (easy)

Solution: Binary Tree Path Sum

All Paths for a Sum (medium)

Solution: All Paths for a Sum

Sum of Path Numbers (medium)

Solution: Sum of Path Numbers

Path With Given Sequence (medium)

Solution: Path With Given Sequence

Count Paths for a Sum (medium)

Solution: Count Paths for a Sum

Problem Challenge 1: Tree Diameter (medium)

Solution: Problem Challenge 1: Tree Diameter

Problem Challenge 2: Path with Maximum Sum (hard)

Solution: Problem Challenge 2: Path with Maximum Sum

Introduction to Graph

Types of Graph

Graph Representations

Graph Traversal - Depth First Search(DFS)

Graph Traversal - Breadth First Search (BFS)

Find if Path Exists in Graph(easy)

Solution: Find if Path Exists in Graph(easy)

Number of Provinces (medium)

Solution: Number of Provinces

Find Eventual Safe States (medium)

Solution: Find Eventual Safe States

Minimum Number of Vertices to Reach All Nodes(medium)

Solution: Minimum Number of Vertices to Reach All Nodes(medium)

Bus Routes (hard)

Solution: Bus Routes

Introduction to Island Pattern

Number of Islands (easy)

Solution: Number of Islands

Biggest Island (easy)

Solution: Biggest Island

Flood Fill (easy)

Solution: Flood Fill

Number of Closed Islands (easy)

Solution: Number of Closed Islands

Problem Challenge 1 (easy)

Solution: Problem Challenge 1

Problem Challenge 2 (medium)

Solution: Problem Challenge 2

Problem Challenge 3 (medium)

Solution: Problem Challenge 3

Introduction to Two Heaps Pattern

Find the Median of a Number Stream (medium)

Solution: Find the Median of a Number Stream

Sliding Window Median (hard)

Solution: Sliding Window Median

Maximize Capital (hard)

Solution: Maximize Capital

Problem Challenge 1: Next Interval (hard)

Solution: Problem Challenge 1: Next Interval

Introduction to Subsets Pattern

Subsets (easy)

Solution: Subsets

Subsets With Duplicates (easy)

Solution: Subsets With Duplicates

Permutations (medium)

Solution: Permutations

String Permutations by changing case (medium)

Solution: String Permutations by changing case

Balanced Parentheses (hard)

Solution: Balanced Parentheses

Unique Generalized Abbreviations (hard)

Solution: Unique Generalized Abbreviations

Problem Challenge 1: Evaluate Expression (hard)

Solution: Problem Challenge 1: Evaluate Expression

Problem Challenge 2: Structurally Unique Binary Search Trees (hard)

Solution: Problem Challenge 2: Structurally Unique Binary Search Trees

Problem Challenge 3: Count of Structurally Unique Binary Search Trees (hard)

Solution: Problem Challenge 3: Count of Structurally Unique Binary Search Trees

Introduction to Modified Binary Search Pattern

Order-agnostic Binary Search (easy)

Solution: Order-agnostic Binary Search

Ceiling of a Number (medium)

Solution: Ceiling of a Number

Next Letter (medium)

Solution: Next Letter

Number Range (medium)

Solution: Number Range

Search in a Sorted Infinite Array (medium)

Solution: Search in a Sorted Infinite Array

Minimum Difference Element (medium)

Solution: Minimum Difference Element

Bitonic Array Maximum (easy)

Solution: Bitonic Array Maximum

Problem Challenge 1: Search Bitonic Array (medium)

Solution: Problem Challenge 1: Search Bitonic Array

Problem Challenge 2: Search in Rotated Array (medium)

Solution: Problem Challenge 2: Search in Rotated Array

Problem Challenge 3: Rotation Count (medium)

Solution: Problem Challenge 3: Rotation Count

Introduction to Bitwise XOR Pattern

Single Number (easy)

Solution: Single Number

Two Single Numbers (medium)

Solution: Two Single Numbers

Complement of Base 10 Number (medium)

Solution: Complement of Base 10 Number

Problem Challenge 1: Flip and Invert an Image (hard)

Solution: Problem Challenge 1: Flip and Invert an Image

Introduction to Top 'K' Elements Pattern

Top 'K' Numbers (easy)

Solution: Top 'K' Numbers

Kth Smallest Number (easy)

Solution: Kth Smallest Number

'K' Closest Points to the Origin (easy)

Solution: 'K' Closest Points to the Origin

Connect Ropes (easy)

Solution: Connect Ropes

Top 'K' Frequent Numbers (medium)

Solution: Top 'K' Frequent Numbers

Frequency Sort (medium)

Solution: Frequency Sort

Kth Largest Number in a Stream (medium)

Solution: Kth Largest Number in a Stream

'K' Closest Numbers (medium)

Solution: 'K' Closest Numbers

Maximum Distinct Elements (medium)

Solution: Maximum Distinct Elements

Sum of Elements (medium)

Solution: Sum of Elements

Rearrange String (hard)

Solution: Rearrange String

Problem Challenge 1: Rearrange String K Distance Apart (hard)

Solution: Problem Challenge 1: Rearrange String K Distance Apart

Problem Challenge 2: Scheduling Tasks (hard)

Solution: Problem Challenge 2: Scheduling Tasks

Problem Challenge 3: Frequency Stack (hard)

Solution: Problem Challenge 3: Frequency Stack

Introduction to K-way Merge Pattern

Merge K Sorted Lists (medium)

Solution: Merge K Sorted Lists

Kth Smallest Number in M Sorted Lists (medium)

Solution: Kth Smallest Number in M Sorted Lists

Kth Smallest Number in a Sorted Matrix (hard)

Solution: Kth Smallest Number in a Sorted Matrix

Smallest Number Range (hard)

Solution: Smallest Number Range

Problem Challenge 1: K Pairs with Largest Sums (hard)

Solution: Problem Challenge 1: K Pairs with Largest Sum

Introduction to Greedy Algorithm

Valid Palindrome II (easy)

Solution: Valid Palindrome II

Maximum Length of Pair Chain (medium)

Solution: Maximum Length of Pair Chain

Minimum Add to Make Parentheses Valid (medium)

Solution: Minimum Add to Make Parentheses Valid

Remove Duplicate Letters (medium)

Solution: Remove Duplicate Letters

Largest Palindromic Number (medium)

Solution: Largest Palindromic Number

Removing Minimum and Maximum From Array (medium)

Solution: Removing Minimum and Maximum From Array

What is Dynamic Programming?

Introduction to 0/1 Knapsack Pattern

0/1 Knapsack (medium)

Solution: 0/1 Knapsack

Equal Subset Sum Partition (medium)

Solution: Equal Subset Sum Partition

Subset Sum (medium)

Solution: Subset Sum

Minimum Subset Sum Difference (hard)

Solution: Minimum Subset Sum Difference

Problem Challenge 1: Count of Subset Sum (hard)

Solution: Problem Challenge 1: Count of Subset Sum

Problem Challenge 2: Target Sum (hard)

Solution: Problem Challenge 2: Target Sum

Introduction to Backtracking Pattern

Combination Sum (medium)

Solution: Combination Sum

Word Search (medium)

Solution: Word Search

Factor Combinations (medium)

Solution: Factor Combinations

Split a String Into the Max Number of Unique Substrings (medium)

Solution: Split a String Into the Max Number of Unique Substrings

Sudoku Solver (hard)

Solution: Sudoku Solver

Introduction to Trie

Implement Trie (Prefix Tree) (medium)

Solution: Implement Trie (Prefix Tree)

Index Pairs of a String (easy)

Solution: Index Pairs of a String

Design Add and Search Words Data Structure (medium)

Solution: Design Add and Search Words Data Structure

Extra Characters in a String (medium)

Solution: Extra Characters in a String

Search Suggestions System (medium)

Solution: Search Suggestions System

Introduction to Topological Sort

Topological Sort (medium)

Solution: Topological Sort

Tasks Scheduling (medium)

Solution: Tasks Scheduling

Tasks Scheduling Order (medium)

Solution: Tasks Scheduling Order

All Tasks Scheduling Orders (hard)

Solution: All Tasks Scheduling Orders

Alien Dictionary (hard)

Solution: Alien Dictionary

Problem Challenge 1: Reconstructing a Sequence (hard)

Solution: Problem Challenge 1: Reconstructing a Sequence

Problem Challenge 2: Minimum Height Trees (hard)

Solution: Problem Challenge 2: Minimum Height Trees

Introduction to Union Find Pattern

Redundant Connection (medium)

Solution: Redundant Connection

Number of Provinces (medium)

Solution: Number of Provinces

Is Graph Bipartite? (medium)

Solution: Is Graph Bipartite?

Path With Minimum Effort (medium)

Solution: Path With Minimum Effort

Introduction to Ordered Set Pattern

Merge Similar Items (easy)

Solution: Merge Similar Items

132 Pattern (medium)

Solution: 132 Pattern

My Calendar I (medium)

Solution: My Calendar I

Longest Continuous Subarray (medium)

Solution: Longest Continuous Subarray

Introduction Prefix Sum Pattern

Find the Middle Index in Array (easy)

Solution: Find the Middle Index in Array

Left and Right Sum Differences (easy)

Solution: Left and Right Sum Differences (easy)

Maximum Size Subarray Sum Equals k (medium)

Solution: Maximum Size Subarray Sum Equals k

Binary Subarrays With Sum (medium)

Solution: Binary Subarrays With Sum

Subarray Sums Divisible by K (medium)

Solution: Subarray Sums Divisible by K

Sum of Absolute Differences in a Sorted Array (medium)

Solution: Sum of Absolute Differences in a Sorted Array

Subarray Sum Equals K (medium)

Solution: Subarray Sum Equals K

Introduction to Multi-threaded Pattern

Same Tree (medium)

Solution: Same Tree

Invert Binary Tree (medium)

Solution: Invert Binary Tree

Binary Search Tree Iterator (medium)

Solution: Binary Search Tree Iterator

Kth Smallest Number (hard)

Solution: Kth Smallest Number

Coding Patterns: A Cheat Sheet

Introduction

Two Sum (easy)

Solution: Two Sum

Valid Perfect Square (easy)