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S.O.L.I.D in Ruby

Scrum: A powerful Agile framework

ActiveRecord Optimization

Optimizing performance by using ActiveRecord properly

Hello 2018

"Hello World, Hello Blog"

Problem: Longest Word in Dictionary

Problem: Implement a Trie

An Easy Way to Understand Algorithm Complexity and Big O Notation

Problem: Logger Rate Limiter

Problem: Roman to Integer

Problem: Shuffle an Array

Problem: Integer to English Words

Problem: Pow(x, n)

Problem: Power of Two

Problem: Multiply Strings

Problem: Rectangle Area

Problem: Rectangle Overlap

Problem: Ugly Number II

Problem: Ugly Number

Problem: String to Integer (atoi)

Problem: Count Primes

Problem: Dungeon Game

Problem: Edit Distance

Problem: Regular Expression Matching

Problem: Frog Jump

Problem: Frog Jump

Problem: Coin Change 2

Problem: Coin Change

Problem: Maximum Product Subarray

Problem: Interleaving String

Problem: Word Break II

Problem: Word Break

Problem: Decode Ways

Problem: Maximum Length of Repeated Subarray

Problem: Maximum Subarray

Problem: Minimum Path Sum

Problem: Best Time to Buy and Sell Stock

Problem: Min Cost Climbing Stairs

Problem: Maximal Square

Problem: Unique Paths II

Problem: Climbing Stairs

Problem: Kth Smallest Element in a Sorted Matrix

Problem: Task Scheduler

Problem: Reorganize String

Problem: Find K Pairs with Smallest Sums

Problem: Find Median from Data Stream

Problem: Merge K Sorted Lists

Problem: Meeting Rooms II

Problem: Top K Frequent Words

Problem: Kth Largest Element in an Array

Problem: Maximal Rectangle

Problem: Flatten Nested List Iterator

Problem: Largest Rectangle in Histogram

Problem: Maximum Frequency Stack

Problem: Next Greater Element II

Problem: Next Greater Element I

Problem: Daily Temperatures

Problem: Design Circular Queue

Problem: Valid Parenthese

Problem: Evaluate Reverse Polish Notation

Problem: Min Stack

Problem: Max Stack

Problem: Implement Queue using Stacks

Problem: Robot Room Cleaner

Problem: Sudoku Solver

Problem: Number of Islands II

Problem: Number of Connected Components in an Undirected Graph

Problem: Matchsticks to Square

Problem: Graph Valid Tree

Problem: All Nodes Distance K in Binary Tree

Problem: Restore IP Addresses

Problem: Pacific Atlantic Water Flow

Problem: The Maze

Problem: Longest Increasing Path in a Matrix

Problem: Decode String

Problem: Subsets II

Problem: Palindrome Permutation II

Problem: Permutations II

Problem: Combination Sum

Problem: Combination Sum III

Problem: Combination Sum II

Problem: Valid Parenthesis String

Problem: Clone Graph

Problem: Generate Parentheses

Problem: Binary Tree Paths

Problem: Word Search

Problem: Word Search II

Problem: Letter Combinations of a Phone Number

Problem: Minesweeper

Problem: Friend Circles

Problem: Number of Distinct Islands

Problem: Making A Large Island

Problem: Number of Islands

Problem: Course Schedule II

Problem: Alien Dictionary

Problem: Minimum Height Trees

Problem: Shortest Distance from All Buildings

Problem: Network Delay Time

Problem: Jump Game II

Problem: Snakes and Ladders

Problem: Binary Tree Vertical Order Traversal

Problem: Word Ladder II

Problem: Word Ladder

Problem: 01 Matrix

Problem: Path Sum III

Problem: Construct Binary Tree from Preorder and Inorder Traversal

Problem: Construct Binary Tree from Inorder and Postorder Traversal

Problem: Find Duplicate Subtrees

Problem: Distribute Coins in Binary Tree

Problem: Contain duplicate III

Problem: Serialize and Deserialize BST

Problem: Serialize and Deserialize Binary Tree

Problem: Convert Sorted List to Binary Search Tree

Problem: Convert Sorted Array to Binary Search Tree

Problem: Minimum Distance Between BST Nodes

Problem: Binary Search Tree Iterator

Problem: Binary Tree Iterative Postorder Traversal

Problem: Binary Tree Iterative Preorder Traversal

Problem: Binary Tree Iterative Inorder Traversal

Problem: Boundary of Binary Tree

Problem: Convert BST to Greater Tree

Problem: Verify Balanced Binary Tree

Problem: Populating Next Right Pointers in Each Node II

Problem: Binary Tree Zigzag Order Level Traversal

Problem: Binary Tree Level Order Traversal

Problem: Lowest Common Ancestor of a Binary Tree

Problem: Lowest Common Ancestor of a Binary Search Trees

Problem: Merge Two Trees

Problem: Symmtric Tree

Problem: Sum Root to Leaf Numbers

Problem: Maximum Width of Binary Tree

Problem: Diameter of Binary Tree

Problem: Binary Tree Maximum Path Sum

Problem: Recover Binary Search Tree

Problem: Validate Binary Search Tree

Problem: kth Smallest in a Binary Search Tree

Problem: Insert into a BST

Problem: Binary Tree Right Side View

Problem: Maximum Depth of Binary Tree

Problem: Binary Tree Min Depth

Problem: LRU Cache

Problem: Swap Nodes in Pairs

Problem: Reorder List

Problem: Odd Even Linked List

Problem: Copy List with Random Pointer

Problem: Add Two Numbers II

Problem: Add Two Numbers

Problem: Palindrome Linked List

Problem: Intersection of Two Linked Lists

Problem: Remove Nth Node from the End of List

Problem: Linked List Cycle

Problem: Reverse Linked List

Problem: Queue Reconstruction by Height

Problem: Wiggle Sort

Problem: Merge Two Sorted Lists

Problem: Merge Sorted Array

Problem: Merge Intervals

Problem: Reorder Log Files

Problem: Meeting Rooms

Problem: Number of Nodes in a Complete Tree

Problem: Find First and Last Position of Element in Sorted Array

Problem: Find K Closest Elements

Problem: Search in Rotated Sorted Array

Problem: Search a 2D Matrix II

Problem: Search a 2D Matrix

Problem: Find Minimum in Rotated Sorted Array

Problem: Single Element in a Sorted Array

Problem: Find peak element

Problem: K-diff Pairs in an Array

Problem: Brick Wall

Problem: Minimum Window Substring

Problem: Number of Boomerangs

Problem: Maximum Size Subarray Sum Equals k

Problem: Contiguous Array

Problem: First Unique Character in a String

Problem: Insert Delete GetRandom O(1)

Problem: Insert Delete GetRandom O(1)

Problem: Valid Anagram

Problem: Sort Characters By Frequency

Problem: Single Number

Problem: Longest Substring Without Repeating Characters

Problem: Longest Consecutive Sequence

Problem: Group Anagrams

Problem: Find All Anagrams in a String

Problem: Contains Duplicate II

Problem: Bulls and Cows

Problem: Next Permutation

Problem: Missing Ranges

Problem: Design Tic-Tac-Toe

Problem: Trapping Rain Water

Problem: Container With Most Water

Problem: Gas Station

Problem: Product of Array Except Self

Problem: Maximum Product of Three Numbers

Problem: Spiral Matrix

Problem: Rotate Image

Problem: Shortest Word Distance

Problem: Rotate Array

Problem: Partition Labels

Problem: Find the Celebrity

Problem: Set Matrix Zeros

Problem: Remove Duplicates from Sorted Array

Problem: Move Zeroes

Problem: Summary Ranges

Problem: String Compression

Problem: Most Common Word

Problem: Find All Duplicates in an Array

Problem: First Missing Positive

Problem: Missing Numbers

Problem: Merge Sorted Array

Problem: Compare Version Numbers

Problem: 3Sum Closest

Problem: Two Sum II - Input array is sorted

Problem: 3sum

Problem: Two Sum

Problem: Longest Substring with At Most Two Distinct Characters

Problem: Palindromic Substrings

Problem: Longest Palindromic Substring