Amazon | BeyondBasics

Amazon

Previous Year Questions

Reorder Data in Log Files

Number of Islands

Critical Connections in a Network

K Closest Points to Origin

Most Common Word

Copy List with Random Pointer

Longest Palindromic Substring

Rotting Oranges

Trapping Rain Water

Merge k Sorted Lists

Partition Labels

Add Two Numbers

Valid Parentheses

Merge Two Sorted Lists

Find Median from Data Stream

Serialize and Deserialize Binary Tree

Top K Frequent Words

Subtree of Another Tree

Search a 2D Matrix II

Concatenated Words

Design Search Autocomplete System

Prison Cells After N Days

Best Time to Buy and Sell Stock

Integer to English Words

Median of Two Sorted Arrays

Longest Substring Without Repeating Characters

Meeting Rooms II

Letter Combinations of a Phone Number

Design Tic-Tac-Toe

Lowest Common Ancestor of a Binary Tree

Product of Array Except Self

Integer to Roman

Sliding Window Maximum

Alien Dictionary

Search in Rotated Sorted Array

Cut Off Trees for Golf Event

Design In-Memory File System

Snakes and Ladders

Compare Version Numbers

Merge Intervals

Insert Delete GetRandom O(1)

Maximum Subarray

Boundary of Binary Tree

Container With Most Water

Minimum Window Substring

Analyze User Website Visit Pattern

Reverse Linked List

Minimum Cost to Connect Sticks

Find the Celebrity

Binary Tree Maximum Path Sum

All Nodes Distance K in Binary Tree

Number of Distinct Islands

Binary Tree Zigzag Level Order Traversal

Reverse Nodes in k-Group

Flatten Nested List Iterator

Validate Binary Search Tree

Implement Trie (Prefix Tree)

Encode and Decode TinyURL

Search Suggestions System

Basic Calculator

Recover Binary Search Tree

Find All Anagrams in a String

Populating Next Right Pointers in Each Node

Generate Parentheses

The Skyline Problem

Basic Calculator III

Binary Tree Vertical Order Traversal

First Unique Character in a String

Construct Binary Tree from Preorder and Inorder Traversal

Kth Largest Element in an Array

Binary Tree Level Order Traversal

Course Schedule

Minimum Path Sum

Largest Rectangle in Histogram

Prime Palindrome

Roman to Integer

Basic Calculator II

Populating Next Right Pointers in Each Node II

Serialize and Deserialize BST

Max Area of Island

Design Hit Counter

Lowest Common Ancestor of a Binary Search Tree

Restore IP Addresses

Minimum Cost to Merge Stones

Search a 2D Matrix

String to Integer (atoi)

Path With Maximum Minimum Value

Diameter of Binary Tree

Number of Distinct Islands II

Binary Search Tree Iterator

Add Two Numbers II

Next Permutation

Palindrome Linked List

Binary Tree Right Side View

Max Points on a Line

Top K Frequent Elements

Design Excel Sum Formula

Design Snake Game

Shuffle an Array

Number of Connected Components in an Undirected Graph

Palindrome Pairs

Employee Free Time

Zigzag Iterator

Shortest Path in Binary Matrix

Maximum Average Subtree

Department Top Three Salaries

Evaluate Reverse Polish Notation

Regular Expression Matching

Find the Closest Palindrome

Two Sum Less Than K

Unique Binary Search Trees

Pacific Atlantic Water Flow

Traffic Light Controlled Intersection

Best Time to Buy and Sell Stock II

Maximum Frequency Stack

Interleaving String

Walls and Gates

Solve the Equation

Combination Sum

Spiral Matrix II

Shortest Distance from All Buildings

Majority Element

Maximum Product Subarray

Next Greater Element II

Course Schedule II

Two Sum II - Input array is sorted

Merge Sorted Array

Count of Smaller Numbers After Self

Add and Search Word - Data structure design

Reverse Linked List II

Number of Dice Rolls With Target Sum

Intersection of Two Linked Lists

Convert BST to Greater Tree

Graph Valid Tree

First Missing Positive

Reconstruct Itinerary

Longest Absolute File Path

Unique Paths III

Longest Valid Parentheses

Longest Consecutive Sequence

Two Sum IV - Input is a BST

Find Minimum in Rotated Sorted Array

Insert Interval

Subarray Sum Equals K

Remove Nth Node From End of List

Convert Sorted List to Binary Search Tree

Nth Highest Salary

Robot Room Cleaner

Reorganize String

Best Time to Buy and Sell Stock III

Next Greater Element I

Daily Temperatures

Largest BST Subtree

Minimum Cost For Tickets

Peeking Iterator

Kth Largest Element in a Stream

Vertical Order Traversal of a Binary Tree

Connecting Cities With Minimum Cost

Swap Nodes in Pairs

Longest Increasing Subsequence

Maximal Rectangle

Linked List Cycle

Inorder Successor in BST

Find K Pairs with Smallest Sums

Best Time to Buy and Sell Stock IV

Moving Average from Data Stream

Climbing Stairs

Next Greater Element III

Find the Duplicate Number

Second Highest Salary

Closest Binary Search Tree Value

Kth Smallest Element in a Sorted Matrix

Single Element in a Sorted Array

Isomorphic Strings

Unique Paths II

Longest Duplicate Substring

Set Matrix Zeroes

Sliding Window Median

Text Justification

Implement Queue using Stacks

Maximum Product of Three Numbers

Find All Duplicates in an Array

Majority Element II

Longest Common Prefix

Cheapest Flights Within K Stops

Longest Substring with At Most K Distinct Characters

Maximum Size Subarray Sum Equals k

Wildcard Matching

Basic Calculator IV

Binary Tree Longest Consecutive Sequence

Longest Increasing Path in a Matrix

Find the Shortest Superstring

Exclusive Time of Functions

Plus One Linked List

Rectangle Overlap

Maximum Depth of Binary Tree

Implement strStr()

Find Duplicate Subtrees

ZigZag Conversion

Evaluate Division

Longest Palindromic Subsequence

Valid Parenthesis String

Substring with Concatenation of All Words

Intersection of Two Arrays

Knight Probability in Chessboard

Time Based Key-Value Store

Capacity To Ship Packages Within D Days

Remove Invalid Parentheses

Divide Two Integers

Binary Search Tree to Greater Sum Tree

Find K-Length Substrings With No Repeated Characters

Find the Town Judge

Split Array With Same Average

Implement Stack using Queues

K-Similar Strings

Kth Smallest Element in a BST

Design Circular Queue

Longest Palindrome

Number of Atoms

Convert Binary Search Tree to Sorted Doubly Linked List

Data Stream as Disjoint Intervals

Valid Tic-Tac-Toe State

Flatten a Multilevel Doubly Linked List

Binary Tree Paths

Surrounded Regions

Binary Tree Inorder Traversal

Palindrome Partitioning

Search in Rotated Sorted Array II

Repeated DNA Sequences

Palindrome Permutation

Reverse Integer

Insert Delete GetRandom O(1) - Duplicates allowed

Diagonal Traverse

Path with Maximum Gold

Stream of Characters

Most Frequent Subtree Sum

Invert Binary Tree

Perfect Squares

Employees Earning More Than Their Managers

Flatten Binary Tree to Linked List

Palindromic Substrings

Convert Sorted Array to Binary Search Tree

Cousins in Binary Tree

Design Log Storage System

Reverse Words in a String II

Pairs of Songs With Total Durations Divisible by 60

Find First and Last Position of Element in Sorted Array

Combine Two Tables

Closest Binary Search Tree Value II

Shortest Path Visiting All Nodes

Shortest Word Distance

Linked List Cycle II

Battleships in a Board

Palindrome Number

Fraction to Recurring Decimal

Last Stone Weight

Island Perimeter

Queue Reconstruction by Height

Longest Turbulent Subarray

Find Peak Element

Find Leaves of Binary Tree

Employee Importance

Partition to K Equal Sum Subsets

Random Pick with Weight

Interval List Intersections

Falling Squares

Insert into a Sorted Circular Linked List

Remove Duplicate Letters

Balanced Binary Tree

Video Stitching

Serialize and Deserialize N-ary Tree

String Compression

Remove K Digits

Number of Digit One

Find K Closest Elements

Sort Characters By Frequency

Android Unlock Patterns

Intersection of Two Arrays II

Smallest Range Covering Elements from K Lists

Longest Substring with At Most Two Distinct Characters

Maximum XOR of Two Numbers in an Array

All O`one Data Structure

Subarrays with K Different Integers

Is Graph Bipartite?

House Robber III

Max Increase to Keep City Skyline

Optimal Account Balancing

Split Array Largest Sum

Valid Palindrome

Minimum Knight Moves

Maximum Width of Binary Tree

Sales Analysis II

Remove Duplicates from Sorted List

Combination Sum II

Stepping Numbers

Asteroid Collision

Remove Duplicates from Sorted List II

Minimum Height Trees

Sentence Similarity II

Sum Root to Leaf Numbers

Excel Sheet Column Number

Odd Even Linked List

Merge Two Binary Trees

First Unique Number

Contiguous Array

Reverse Words in a String

Line Reflection

Fibonacci Number

One Edit Distance

Online Stock Span

Meeting Scheduler

Super Washing Machines

Find Winner on a Tic Tac Toe Game

Sum of Root To Leaf Binary Numbers

Global and Local Inversions

Remove Duplicates from Sorted Array

Minimum Genetic Mutation

Single Number II

Department Highest Salary

Max Consecutive Ones III

Trapping Rain Water II

Combination Sum IV

Construct Binary Tree from Inorder and Postorder Traversal

Design File System

Find the Derangement of An Array

Split Linked List in Parts

Palindrome Partitioning II

Unique Email Addresses

Count Univalue Subtrees

Pascal's Triangle

Contains Duplicate

Permutation Sequence

Best Meeting Point

Couples Holding Hands

Valid Triangle Number

Minimum Size Subarray Sum

Reverse Words in a String III

Find K-th Smallest Pair Distance

UTF-8 Validation

Insert into a Binary Search Tree

Jewels and Stones

Repeated String Match

Reverse String II

Average of Levels in Binary Tree

Network Delay Time

Water and Jug Problem

Longest Substring with At Least K Repeating Characters

Nested List Weight Sum

Maximum Sum of Two Non-Overlapping Subarrays

Relative Sort Array

Minimum Depth of Binary Tree

Sum of Two Integers

Logical OR of Two Binary Grids Represented as Quad-Trees

Backspace String Compare

Russian Doll Envelopes

Maximum Level Sum of a Binary Tree

Arithmetic Slices

Find Largest Value in Each Tree Row

Construct Quad Tree

Delete Node in a BST

Validate IP Address

Number of Islands II

Find Common Characters

Dinner Plate Stacks

Number of Days Between Two Dates

Next Greater Node In Linked List

Matchsticks to Square

Minimum Window Subsequence

Customers Who Never Order

Minimum Cost Tree From Leaf Values

Multiply Strings

Maximize Distance to Closest Person

Count Complete Tree Nodes

Range Sum Query 2D - Immutable

Campus Bikes II

Partition Equal Subset Sum

Minimum Difficulty of a Job Schedule

Different Ways to Add Parentheses

Binary Tree Postorder Traversal

Maximum Sum BST in Binary Tree

Longest Univalue Path

Permutations II

Design Bounded Blocking Queue

Delete Node in a Linked List

Number of Submatrices That Sum to Target

Maximum Length of Pair Chain

Minimize Malware Spread

Create Maximum Number

Sales Analysis III

Permutation in String

Range Sum Query - Mutable

Pancake Sorting

Construct Binary Tree from Preorder and Postorder Traversal

Distinct Subsequences

Smallest Subsequence of Distinct Characters

Longest Common Subsequence

Shortest Palindrome

Reverse Vowels of a String

Minimum Distance Between BST Nodes

Consecutive Numbers

Students Report By Geography

Binary Tree Level Order Traversal II

Sort Array By Parity

Lemonade Change

Shortest Unsorted Continuous Subarray

Increasing Triplet Subsequence

Elimination Game

Find Cumulative Salary of an Employee

Trips and Users

Longest Happy String

Strong Password Checker

Making A Large Island

Sum of Nodes with Even-Valued Grandparent

Longest Repeating Substring

Number of Boomerangs

K-diff Pairs in an Array

Get Watched Videos by Your Friends

Middle of the Linked List

Random Pick with Blacklist

Maximum Sum Circular Subarray

Number of 1 Bits

Length of Longest Fibonacci Subsequence

Customer Placing the Largest Number of Orders

Robot Return to Origin

Design A Leaderboard

Range Sum of BST

Unique Binary Search Trees II

Remove Linked List Elements

Logger Rate Limiter

Complete Binary Tree Inserter

Maximum Depth of N-ary Tree

Read N Characters Given Read4 II - Call multiple times

Path In Zigzag Labelled Binary Tree

Linked List Random Node

My Calendar III

Minimum Domino Rotations For Equal Row

Shortest Word Distance II

Third Maximum Number

Defanging an IP Address

Partition Array Into Three Parts With Equal Sum

Pascal's Triangle II

Largest 1-Bordered Square

Min Cost Climbing Stairs

Minimum Moves to Equal Array Elements

Count The Repetitions

Managers with at Least 5 Direct Reports

Find Duplicate File in System

Prime Number of Set Bits in Binary Representation

Largest Divisible Subset

Boats to Save People

Minimum Number of Arrows to Burst Balloons

Remove All Adjacent Duplicates In String

K-th Symbol in Grammar

All People Report to the Given Manager

Search Insert Position

Integer Replacement

Subdomain Visit Count

Sparse Matrix Multiplication

Minimum Area Rectangle

Non-overlapping Intervals

Trim a Binary Search Tree

Shortest Subarray with Sum at Least K

Minimum Remove to Make Valid Parentheses

Smallest String With Swaps

Design Compressed String Iterator

Construct Binary Search Tree from Preorder Traversal

Number of Closed Islands

Bulb Switcher III

Missing Element in Sorted Array

Human Traffic of Stadium

Find Smallest Common Element in All Rows

Pyramid Transition Matrix

Rearrange String k Distance Apart

Minimum Number of K Consecutive Bit Flips

Shortest Path to Get All Keys

Binary Tree Longest Consecutive Sequence II

Next Closest Time

Redundant Connection

Contains Duplicate II

Number of Matching Subsequences

Peak Index in a Mountain Array

Construct Binary Tree from String

String Transforms Into Another String

Minimum Number of Refueling Stops

Predict the Winner

Longest Arithmetic Sequence

Squares of a Sorted Array

Continuous Subarray Sum

Count Number of Nice Subarrays

Array Partition I

Score of Parentheses

Design Linked List

As Far from Land as Possible

Check If a String Is a Valid Sequence from Root to Leaves Path in a Binary Tree

Maximum Difference Between Node and Ancestor

Minimum Area Rectangle II

Longest String Chain

Longest Word in Dictionary

Sum of Left Leaves

Find Pivot Index

Minimum Time Difference

Distribute Coins in Binary Tree

Web Crawler Multithreaded

Count Number of Teams

Flip Equivalent Binary Trees

DI String Match

House Robber II

Best Time to Buy and Sell Stock with Transaction Fee

Wiggle Subsequence

Number of Longest Increasing Subsequence

Maximize Sum Of Array After K Negations

Search in a Sorted Array of Unknown Size

N-ary Tree Level Order Traversal

Sales by Day of the Week

Find Words That Can Be Formed by Characters

Best Time to Buy and Sell Stock with Cooldown

Check Completeness of a Binary Tree

Subarray Sums Divisible by K

All Paths from Source Lead to Destination

Remove Sub-Folders from the Filesystem

Find and Replace Pattern

Maximum Binary Tree

Letter Case Permutation

Similar String Groups

Fruit Into Baskets

Replace Elements with Greatest Element on Right Side

Reformat Department Table

Binary Tree Preorder Traversal

Second Minimum Node In a Binary Tree

Product Sales Analysis I

Split Array into Fibonacci Sequence

Delete Duplicate Emails

Closest Leaf in a Binary Tree

Vowel Spellchecker

Group Shifted Strings

Factorial Trailing Zeroes

Minimum Time Visiting All Points

Rotate Function

Palindrome Permutation II

Max Consecutive Ones

Delete Nodes And Return Forest

Camelcase Matching

Hamming Distance

Can Place Flowers

Most Profit Assigning Work

Valid Perfect Square

Custom Sort String

Combination Sum III

Minimum Swaps to Make Strings Equal

Minimum Add to Make Parentheses Valid

Repeated Substring Pattern

First Bad Version

Uncommon Words from Two Sentences

Koko Eating Bananas

Longest Continuous Increasing Subsequence

Sales Analysis I

Single Number III

Verifying an Alien Dictionary

Binary Tree Pruning

The K Weakest Rows in a Matrix

Friendly Movies Streamed Last Month

Leaf-Similar Trees

Find Customer Referee

Remove Palindromic Subsequences

Two City Scheduling

Average Selling Price

Minimum Swaps To Make Sequences Increasing

Product Sales Analysis II

Minimum Falling Path Sum

Remove Duplicates from Sorted Array II

Sort Array By Parity II

Split a String in Balanced Strings

Find the Team Size

Maximum Product of Splitted Binary Tree

Number of Equivalent Domino Pairs

Count Servers that Communicate

Balance a Binary Search Tree

Maximum Number of Vowels in a Substring of Given Length

Univalued Binary Tree

N-ary Tree Postorder Traversal

Last Stone Weight II

All Paths From Source to Target

Customer Order Frequency

Construct String from Binary Tree

Find N Unique Integers Sum up to Zero

Delete Leaves With a Given Value

Angle Between Hands of a Clock

Find Mode in Binary Search Tree

Range Sum Query - Immutable

Non-decreasing Array

Maximum Number of Non-Overlapping Substrings

Find Minimum in Rotated Sorted Array II

Find the Difference

How Many Numbers Are Smaller Than the Current Number

Count Negative Numbers in a Sorted Matrix

Kids With the Greatest Number of Candies

Equal Tree Partition

Complex Number Multiplication

Optimal Division

Monotone Increasing Digits

Numbers At Most N Given Digit Set

Digit Count in Range

Index Pairs of a String

Sum of Digits in the Minimum Number

Number of Days in a Month

Remove Vowels from a String

Armstrong Number

Recover a Tree From Preorder Traversal

Largest Unique Number

Uncrossed Lines

Customers Who Bought All Products

Actors and Directors Who Cooperated At Least Three Times

Distant Barcodes

Product Sales Analysis III

Insufficient Nodes in Root to Leaf Paths

Handshakes That Don't Cross

Remove Covered Intervals

Shortest Path with Alternating Colors

Closest Divisors

Largest Multiple of Three

Prime Arrangements

Diet Plan Performance

Maximum Score Words Formed by Letters

All Elements in Two Binary Search Trees

List the Products Ordered in a Period

Students With Invalid Departments

Number of Steps to Reduce a Number in Binary Representation to One

String Matching in an Array

Queries on a Permutation With Key

Pseudo-Palindromic Paths in a Binary Tree

Find Critical and Pseudo-Critical Edges in Minimum Spanning Tree

Clone Binary Tree With Random Pointer

Can Make Arithmetic Progression From Sequence

Clone N-ary Tree

Find the Index of the Large Integer

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