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Coding Interview Patterns
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Sliding Window
Sliding Window: Introduction
Repeated DNA Sequences
Solution: Repeated DNA Sequences
Find Maximum in Sliding Window
Solution: Find Maximum in Sliding Window
Minimum Window Subsequence
Solution: Minimum Window Subsequence
Longest Repeating Character Replacement
Solution: Longest Repeating Character Replacement
Minimum Window Substring
Solution: Minimum Window Substring
Longest Substring without Repeating Characters
Solution: Longest Substring without Repeating Characters
Minimum Size Subarray Sum
Solution: Minimum Size Subarray Sum
Best Time to Buy and Sell Stock
Two Pointers
Two Pointers: Introduction
Valid Palindrome
Solution: Valid Palindrome
Sum of Three Values
Solution: Sum of Three Values
Remove Nth Node from End of List
Solution: Remove Nth Node from End of List
Sort Colors
Solution: Sort Colors
Reverse Words in a String
Solution: Reverse Words in a String
Valid Palindrome II
Fast and Slow Pointers
Fast and Slow Pointers: Introduction
Happy Number
Solution: Happy Number
Linked List Cycle
Solution: Linked List Cycle
Middle of the Linked List
Solution: Middle of the Linked List
Circular Array Loop
Solution: Circular Array Loop
Find the Duplicate Number
Solution: Find the Duplicate Number
Palindrome Linked List
Solution: Palindrome Linked List
Merge Intervals
Merge Intervals: Introduction
Merge Intervals
Solution: Merge Intervals
Insert Interval
Solution: Insert Interval
Interval List Intersections
Solution: Interval List Intersections
Employee Free Time
Solution: Employee Free Time
Task Scheduler
Solution: Task Scheduler
Meeting Rooms II
In-place Reversal of a Linked List
In-place Reversal of a Linked List: Introduction
Reverse Linked List
Solution: Reverse Linked List
Reverse Nodes in k-Group
Solution: Reverse Nodes in k-Group
Reverse Linked List II
Solution: Reverse Linked List II
Reorder List
Solution: Reorder List
Swapping Nodes in a Linked List
Solution: Swapping Nodes in a Linked List
Reverse Nodes In Even Length Groups
Solution: Reverse Nodes in Even Length Groups
Swap Nodes in Pairs
Two Heaps
Two Heaps: Introduction
Maximize Capital
Solution: Maximize Capital
Sliding Window Median
Solution: Sliding Window Median
Find Median from a Data Stream
Solution: Find Median from a Data Stream
Schedule Tasks on Minimum Machines
Solution: Schedule Tasks on Minimum Machines
K-way merge
K-way Merge: Introduction
Merge Sorted Array
Solution: Merge Sorted Array
Kth Smallest Number in M Sorted Lists
Solution: Kth Smallest Number in M Sorted Lists
Find K Pairs with Smallest Sums
Solution: Find K Pairs with Smallest Sums
Merge K Sorted Lists
Solution: Merge K Sorted Lists
Kth Smallest Element in a Sorted Matrix
Solution: Kth Smallest Element in a Sorted Matrix
Top K Elements
Top K Elements: Introduction
Kth Largest Element in a Stream
Solution: Kth Largest Element in a Stream
Reorganize String
Solution: Reorganize String
K Closest Points to Origin
Solution: K Closest Points to Origin
Top K Frequent Elements
Solution: Top K Frequent Elements
Kth Largest Element in an Array
Solution: Kth Largest Element in an Array
Top K Frequent Words
Modified Binary Search
Modified Binary Search: Introduction
Binary Search
Solution: Binary Search
Search in Rotated Sorted Array
Solution: Search in Rotated Sorted Array
First Bad Version
Solution: First Bad Version
Random Pick with Weight
Solution: Random Pick with Weight
Find K Closest Elements
Solution: Find K Closest Elements
Single Element in a Sorted Array
Solution: Single Element in a Sorted Array
Search in Rotated Sorted Array II
Subsets
Subsets: Introduction
Subsets
Solution: Subsets
Permutations
Solution: Permutations
Letter Combinations of a Phone Number
Solution: Letter Combinations of a Phone Number
Generate Parentheses
Solution: Generate Parentheses
Find K-Sum Subsets
Greedy Techniques
Greedy Techniques: Introduction
Jump Game I
Solution: Jump Game I
Boats to Save People
Solution: Boats to Save People
Gas Stations
Solution: Gas Stations
Two City Scheduling
Solution: Two City Scheduling
Minimum Number of Refueling Stops
Solution: Minimum Number of Refueling Stops
Jump Game II
Backtracking
Backtracking: Introduction
N-Queens
Solution: N-Queens
Word Search
Solution: Word Search
House Robber III
Solution: House Robber III
Restore IP Addresses
Solution: Restore IP Addresses
Flood Fill
Solution: Flood Fill
Sudoku Solver
Matchsticks to Square
Dynamic Programming
Dynamic Programming: Introduction
0/1 Knapsack
Solution: 0/1 Knapsack
Coin Change
Solution: Coin Change
N-th Tribonacci Number
Solution: N-th Tribonacci Number
Partition Equal Subset Sum
Solution: Partition Equal Subset Sum
Counting Bits
Solution: Counting Bits
01 Matrix
Solution: 01 Matrix
House Robber II
Solution: House Robber II
Maximum Product Subarray
Solution: Maximum Product Subarray
Combination Sum
Solution: Combination Sum
Word Break
Solution: Word Break
Palindromic Substrings
Solution: Palindromic Substrings
Longest Common Subsequence
Solution: Longest Common Subsequence
Word Break II
Solution: Word Break II
Decode Ways
Solution: Decode Ways
Climbing Stairs
Cyclic Sort
Cyclic Sort: Introduction
Missing Number
Solution: Missing Number
First Missing Positive
Solution: First Missing Positive
Find the Corrupt Pair
Solution: Find the Corrupt Pair
Find the First K Missing Positive Numbers
Topological Sort
Topological Sort: Introduction
Compilation Order
Solution: Compilation Order
Alien Dictionary
Solution: Alien Dictionary
Verifying an Alien Dictionary
Solution: Verifying an Alien Dictionary
Course Schedule II
Solution: Course Schedule II
Course Schedule
Solution: Course Schedule
Find All Possible Recipes from Given Supplies
Matrices
Introduction to Matrices
Set Matrix Zeroes
Solution: Set Matrix Zeroes
Rotate Image
Solution: Rotate Image
Spiral Matrix
Solution: Spiral Matrix
Where Will the Ball Fall
Solution: Where Will the Ball Fall
Stacks
Stacks: Introduction
Basic Calculator
Solution: Basic Calculator
Remove All Adjacent Duplicates In String
Solution: Remove All Adjacent Duplicates In String
Minimum Remove to Make Valid Parentheses
Solution: Minimum Remove to Make Valid Parentheses
Exclusive Execution Time of Functions
Solution: Exclusive Execution Time of Functions
Flatten Nested List Iterator
Solution: Flatten Nested List Iterator
Implement Queue Using Stacks
Solution: Implement Queue Using Stacks
Valid Parentheses
Graphs
Introduction to Graphs
Network Delay Time
Solution: Network Delay Time
Paths in Maze That Lead to Same Room
Solution: Paths in Maze That Lead to Same Room
Clone Graph
Solution: Clone Graph
Graph Valid Tree
Solution: Graph Valid Tree
Bus Routes
Solution: Bus Routes
Tree Depth First Search
Tree Depth-first Search: Introduction
Flatten Binary Tree to Linked List
Solution: Flatten Binary Tree to Linked List
Diameter of Binary Tree
Solution: Diameter of Binary Tree
Serialize and Deserialize Binary Tree
Solution: Serialize and Deserialize Binary Tree
Invert Binary Tree
Solution: Invert Binary Tree
Binary Tree Maximum Path Sum
Solution: Binary Tree Maximum Path Sum
Convert Sorted Array to Binary Search Tree
Solution: Convert Sorted Array to Binary Search Tree
Build Binary Tree from Preorder and Inorder Traversal
Solution: Build Binary Tree from Preorder and Inorder Traversal
Binary Tree Right Side View
Solution: Binary Tree Right Side View
Lowest Common Ancestor of a Binary Tree
Solution: Lowest Common Ancestor of a Binary Tree
Validate Binary Search Tree
Solution: Validate Binary Search Tree
Maximum Depth of Binary Tree
Kth Smallest Element in a BST
Tree Breadth First Search
Tree Breadth-first Search: Introduction
Level Order Traversal of Binary Tree
Solution: Level Order Traversal of Binary Tree
Binary Tree Zigzag Level Order Traversal
Solution: Binary Tree Zigzag Level Order Traversal
Populating Next Right Pointers in Each Node
Solution: Populating Next Right Pointers in Each Node
Vertical Order Traversal of a Binary Tree
Solution: Vertical Order Traversal of a Binary Tree
Connect All Siblings of a Binary Tree
Symmetric Tree
Solution: Symmetric Tree
Word Ladder
Solution: Word Ladder
Connect All Siblings of a Binary Tree
Trie
Trie: Introduction
Implement Trie
Solution: Implement Trie
Search Suggestions System
Solution: Search Suggestions System
Replace Words
Solution: Replace Words
Design Add and Search Words Data Structure
Solution: Design Add and Search Words Data Structure
Word Search II
Solution: Word Search II
Lexicographical Numbers
Hash Maps
Hash Maps: Introduction
Design HashMap
Solution: Design HashMap
Fraction to Recurring Decimal
Solution: Fraction to Recurring Decimal
Logger Rate Limiter
Solution: Logger Rate Limiter
Next Greater Element
Solution: Next Greater Element
Isomorphic Strings
Solution: Isomorphic Strings
Longest Palindrome
Knowing What to Track
Knowing What to Track: Introduction
Palindrome Permutation
Solution: Palindrome Permutation
Valid Anagram
Solution: Valid Anagram
Design Tic-Tac-Toe
Solution: Design Tic-Tac-Toe
Group Anagrams
Solution: Group Anagrams
Maximum Frequency Stack
Solution: Maximum Frequency Stack
First Unique Character in a String
Solution: First Unique Character in a String
Find All Anagrams in a String
Solution: Find All Anagrams in a String
Longest Palindrome by Concatenating Two-Letter Words
Solution: Longest Palindrome by Concatenating Two-Letter Words
Ransom Note
Union Find
Union Find: Introduction
Redundant Connection
Solution: Redundant Connection
Number of Islands
Solution: Number of Islands
Most Stones Removed with Same Row or Column
Solution: Most Stones Removed with Same Row or Column
Longest Consecutive Sequence
Solution: Longest Consecutive Sequence
Last Day Where You Can Still Cross
Solution: Last Day Where You Can Still Cross
Regions Cut by Slashes
Solution: Regions Cut by Slashes
Accounts Merge
Solution: Accounts Merge
Minimize Malware Spread
Solution: Minimize Malware Spread
Evaluate Division
Custom Data Structures
Custom Data Structures: Introduction
Snapshot Array
Solution: Snapshot Array
Time-Based Key-Value Store
Solution: Time-Based Key-Value Store
Implement LRU Cache
Solution: Implement LRU Cache
Insert Delete GetRandom O(1)
Solution: Insert Delete GetRandom O(1)
Min Stack
Solution: Min Stack
LFU Cache
Bitwise Manipulation
Bitwise Manipulation: Introduction
Find the Difference
Solution: Find the Difference
Complement of Base 10 Number
Solution: Complement of Base 10 Number
Flipping an Image
Solution: Flipping an Image
Single Number
Solution: Single Number
Two Single Numbers
Solution: Two Single Numbers
Encode and Decode Strings
Solution: Encode and Decode Strings
Reverse Bits
Challenge Yourself
Challenge Yourself: Introduction
Shortest Bridge
Number of Connected Components in an Undirected Graph
Median of Two Sorted Arrays
Pacific Atlantic Water Flow
Contains Duplicate
Two Sum
Find Minimum in Rotated Sorted Array
Non-overlapping Intervals
Meeting Rooms
Largest Rectangle in Histogram
Subtree of Another Tree
Sort List
Number of 1 Bits
Container With the Most Water
Evaluate Reverse Polish Notation
4Sum
Loud and Rich
Product of Array Except Self
Longest Increasing Subsequence
Sum of Two Integers
Majority Element
Unique Paths
Longest Palindromic Substring
Permutations II
Number of Provinces
Linked List Cycle II
Minimum Flips to Make the Binary String Alternate
Lemonade Change
House Robber
Find All Numbers Disappeared in an Array
Find All Duplicates in an Array
Same Tree
Design In-Memory File System
Design File System
Asteroid Collision
Rotting Oranges
Add Binary
Multiply Strings
Conclusion
Final Remarks
Let's solve the Symmetric Tree problem using the Tree BFS pattern.
We'll cover the following
Statement
Solution
Time complexity
Space complexity