Leetcode  ⁴⁴⁰

Length Of Last Word

Wildcard Matching

Multiply Strings

Valid Sudoku

Sudoku Solver

Longest Valid Parantheses

Substring With Concatenation Of All Words

Divide Two Integers

Find The Index Of The First Occurence In A String

Smallest Divisible Digit Product 1

Remove Duplicates From Sorted Array

Remove Element

Reverse Nodes In K Group

Reverse Linked List

Merge 2 Sorted Lists

Generate Parantheses

Longest Common Prefix

3 Sum

Integer To Roman

Roman To Integer

String To Integer (atoi)

Palindrome Number

Zigzag Conversion

Median Of Two Sorted Arrays

Add 2 Numbers

Maximise Active Section With Trade 1

Recover Tree From Preorder Traversal

Shift 2d Grid

Smallest Subsequence Of Distinct Characters

Concatenate Non Zero Digits And Multiply By Sum 2

Rank Transform Of An Array

Path Existence Queries In A Graph 1

Remove Covered Intervals

Number Of Paths With Max Score

Network Recovery Pathways

Minimum Score Of A Path Between 2 Cities

Find The Safest Path In A Grid

Find A Safe Walk Through A Grid

Number Of Strings That Appear As Substring In Word

Count Subarrays With Majority Element 2

Find The Maximum Number Of Elements In A Subset

Number of Zig-Zag Arrays 1

Process String With Special Operations 2

Maximum Ice Cream Bars

Max Number Of Balloons

Angle Between Hands Of A Clock

Find The Highest Altitude

Process String With Special Operations 1

Delete The Middle Node Of A Linked List

Number Of Ways To Assign Edge Weights 1

Weighted Word Mapping

Create Binary Tree From Descriptions

Left And Right Sum Differences

Total Waviness Of Numbers In Range 1

Minimum Cost Of Buying Candies With Discount

Earliest Finish Time For Land And Water Rides 2

Maximum Number Of Items From Sale 1

Destroying Asteroids

Minimum Element After Replacing With Digit Sum

Longest Common Suffix Queries

Count The Number Of Special Characters 2

Jump Game 7

Count The Number Of Special Characters 1

Jump Game 5

Minimum Moves To Make Array Complementary

Find The Length Of The Longest Common Prefix

Maximum Walls Destroyed By Robots

Jump Game 4

Jump Game 3

Find Minimum In Rotated Sorted Array

Minimum Initial Energy To Finish Tasks

Maximum Number Of Jumps To Reach The Last Index

Minimum Jumps To Reach End Via Prime

Jump Game 9

Robot Collisions

Maximum Size Of Set After Removals

Rotate List

Rotate Image

Rotate String

Lexicographically Smallest Generated String

Rotated Digits

Rotate Function

Minimum Distance To Type A Word Using 2 Different Fingers

Find The String With LCP

Maximise Amount After 2 Days Of Conversions

Maximise The Distance Between Points On A Square

Minimum Operations To Make Array Non Decreasing

Check If There Is A Valid Path In The Grid

Detect Cycles In 2d Grid

Longest Balanced String After One Swap

Sum Of Distances

Furthest Point From Origin

Minimize Hamming Distance After Swap Operations

Words Within 2 Edits Of Dictionary

Maximum Distance Between A Pair Of Values

2 Farthest Houses With Different Colors

Adding Spaces To A String

Multi Source Flood Fill

Minimum Moves To Spread Stones Over Grid

Minimum Absolute Distance Between Mirror Pairs

Closest Equal Element Queries

Can Place Flowers

Maximise Spanning Tree Stability With Upgrades

Maximum Swap

Equal Sum Grid Partition 2

Minimum Increase To Maximise Special Indices

Minimum Distance Between 3 Equal Elements

Incremental Even Weighted Cycle Queries

Possible Bipartition

Mirror Frequency Text

Integers With Multiple Sum Of Two Cubes

Decode Slanted Ciphertext

Directions Assignments With Exactly K Visible People

Maximum Amount Of Money Robot Can Earn

Cousins In A Binary Tree 2

Cousins In A Binary Tree 1

Count Number Of Nice Subarrays

Check If Strings Can Be Made Equal With Operations 2

Check If Strings Can Be Made Equal With Operations 1

Equal Sum Grid Partition 1

Minimum Absolute Difference Between 2 Values

Minimum Xor Path In A Grid

Design Event Manager

Matrix Similarity After Cyclic Shifts

Minimum Absolute Difference In A Sliding Matrix

Construct Product Matrix

Maximum Non Negative Product In A Matrix

Check Whether Matrix Can Be Obtained By Rotation

Largest Submatrix With Rearrangements

Count Submatrices With Top Element And Sum Less Than K

Count Submatrices With Equal Frequency Of X And Y

Greatest Common Divisor Of Strings

Walking Robot Simulation

Minimized Maximum Of Products Distributed To Any Store

Sequential Digits

Minimum Changes To Make Alternating Binary String

Binary Subarrays With Sum

Special Positions In A Binary Matrix

Find Nth Bit In Kth Binary String

Minimum Swaps To Arrange A Binary Grid

Minimum Operations To Equalize Binary String

Partitioning Into Maximum Number Of Deci Binary Numbers

Merge Close Characters

Check If A String Contains All Binary Strings Of Size K

Special Binary String

Count Binary Substrings

Champagne Tower

Longest Balanced Subarray 1

Longest Balanced Subarray 1

Balance A Binary Search Tree

Minimum Deletions To Make String Balanced

Minimum Number Of Removals To Balance An Array

Trionic Array 1

Divide An Array Into Subarrays With Minimum Cost 1

Minimum Cost To Convert String 1

Rotate Non Negative Elements

Minimum Cost Path With Edge Reversals

Minimize Maximum Pair Sum In An Array

Maximum Side Length Of A Square With Sum Less Than Or Equal To Threshold

Largest Magic Square

Find The Largest Area Of Square Inside Rectangles

Maximum Square Area By Removing Fences From A Field

Maximize Area Of Square Hole In Grid

Separate Squares 1

Minimum Time Visiting All Points

Minimum Ascii Delete Sum For 2 Strings

Max Dot Product Of 2 Subsequences

Maximum Product Of Split Binary Tree

Maximum Matrix Sum

Number Of Increasing Paths In A Grid

4 Divisors

Number Of Ways To Paint Nx3 Grid

Last Day When You Can Still Cross

Pyramid Transition Matrix

Amazon’s - 926. Flip String Monotone Increasing

Next Permutation

Meeting Rooms 3

Minimum Penalty For A Shop

Maximise Happiness Of Selected Children

Minimum Cost To Cut A Stick

Two Best Non Overlapping Events

Apple Redistribution Into Boxes

Delete Columns To Make Sorted 3

Delete Columns To Make Sorted 2

Delete Columns To Make Sorted

Number Of Smooth Decent Periods Of A Stock

Number Of Ways To Divide A Long Corridor

Permutations 2

IPO

Count Covered Buildings

Count Special Triplets

Count Number Of Odd Numbers In An Interval Range

Count Number Of Collissions On A Road

Amount Of Time For Binary Tree To Be Infected

Make Sum Divisible By P

Maximum Number Of K Divisible Components

Maximum Subarray Sum With Length Divisible By K

Subarray Sums Divisible By K

Paths In A Matrix Divisible By 5

Smallest Integer Divisible By K

Binary Prefix Divisible By 5

Greatest Sum Divisible By 3

Unique Length 3 Palindromic Subsequences

Set Intersection Size Of Atleast 2

1 Bit And 2 Bit Characters

Number Of Substrings With Only Ones

Count The Number Of Substrings With Dominant Ones

Increment Submatrices By One

Maximum Number Of Operations To Move Ones To End

Minimum Number Of Operations To Convert All Elements To Zero

Minimum Number Of Operations To Make Array Elements Equal To 1

Ones And Zeroes

Maximize The Minimum Powered City

Power Grid Maintenance

Find X Sum Of All K Long Subarrays 2

Find X Sum Of All K Long Subarrays 1

Minimum Time To Make Rope Colorful

Count Unguarded Cells In The Grid

Delete Nodes From Linked List Present In Array

All Nodes Distance K In Binary Tree

Minimum Number of Increments To Reach Target Subarray

Smallest Number With All Set Bits

Make Array Elements Zero

Number Of Laser Beams In A Bank

Next Greater Numericaly Balanced Number

Maximum Frequency Of An Element After Performing Operations 2

Lexicographically Smallest String After Applying Operations

Maximum Number Of Distinct Elements After Operations

Smallest Non Negative Number After Operations

Adjacent Increasing Subarrays Detection 2

Adjacent Increasing Subarrays Detection 1

Design Movie Rental System

Max Energy From Mystic Dungeon

Minimum Amount Of Time To Brew Potions

Successful Pairs Of Spells And Potions

Avoid Flood In The City

Swim In Rising Water

Trapping Rain Water 2

Num Bottles 2

Find Triangular Sum Of Array

Minimum Score Triangulation Of Polygon

Largest Perimeter Triangle

Valid Triangle Number

Fraction To Decimal

Implement Router

Compare Version Numbers

Count Elements With Maximum Frequency

Design A Food Rating System

Remove Coprimes From Array

Vowels Game In String

Sort Vowels In String

Min Number Of People To Teach

Find N Unique Integers Sum Up To Zero

Minimum Operations To Make Integer Zero

Max Average Pass Ratio

Number Of Ways To Place People 1

Alice And Bob Playing Flower Game

Sort Matrix By Diagonals

Diagonal Traverse

Min Area To Cover All 1s

Power Of 2

Fruit Into Baskets

Longest Subarray With Maximum Bitwise And

Bitwise Ors Of Subarrays

Count Max Number Of Bitwise Or Subsets

Count Hills And Valleys In An Array

Max Score From Removing Substrings

Maxiumum Erasure Value

Remove Subfolders From The File System

Find Maximum Length Of Subsequence 1

Longest Binary Sequence Less Than K

Lexicographically Minimum String After Removing Stars

Min Swaps To Sort By Digit Sum

Longest Unequal Adjacent Groups Subsequence 1

Finding 3-Digit Even Numbers

Max Total Damage With Spell Casting

Minimum Domino Rotations For Equal Row

Microsoft’s - 838. Push Dominoes

Count Subarrays Where Max Element Appears Atleast K Times

Count Subarrays Of Length Three With Condition

Find The Most Common Response

Unit Conversion 1

Count Complete Subarrays In An Array

Count Largest Group

Longest Subarray After Deleting One Element

Max Consecutive Ones 3

Minimize Difference Between Target And Chosen Elements

Frequency Of Most Frequent Element

Count And Say

Maximal Rectangle

Sum Of Subarray Sums

Lca Of Deepest Leaves

Max Value Of An Ordered Triplet 2

Unique 3 Digit Even Numbers

Design Spreadsheet

Max Value Of An Ordered Triplet

Next Greater Node In Linked List

Remove Nodes From Linked List

Google’s - 1673. Find The Most Competitive Subsequence

Put Marbles In Bags

Microsoft’s - 316. Remove Duplicate Letters

Swap Nodes In Pairs

Substring Matching Pattern

Apply Operations To Maximise Score

Max Number Of Points From Grid Queries

Spiral Matrix 2

3 Sum Closest Sum

Min Operations To Make Uni Value Grid

Random Pick With Weight

Simple Bank System

Zero Array Transformation 1

Number Of Substrings Containing All 3 Characters

Count Of Substrings Containing Every Vowel And K Consonants 2

Subarrays With K Different Integers

Partition Array According To Given Plot

Meta’s - 1582. Min Cost To Connect All Nodes

Meta’s - 1584. Min Cost To Connect All Nodes

Number Of Subarrays With Odd Sum

Max Absolute Sum Of Any Subarray

Eliminate Max Number Of Monsters

First Missing Positive

Google’s - 1161. Max Level Sum Of Binary Tree

Kth Lexicographical String Of All Happy Strings Of Length N

Count Square Submatrices With All Ones

Minimum Number Of Flips To Make Binary String Alternating

Reverse Integer

4 Sum

Matchsticks To Square

Min Difference Between Highest And Lowest Of K Scores

Check If Array Is Sorted And Rotated

Microsoft’s - 2477. Minimum Fuel Cost To Report To The Capital

Is Graph Bipartite

Out Of Boundary Paths

Permutations

Path With Max Probability

Network Delay Time

Reverse Words In String

Valid Paranthesis

Merge Intervals

Insert Intervals

Balanced Binary Tree

Find The Common Array Of 2 Arrays

Pacific Atlantic Flow

Pow X

Search In Rotated Sorted Array

Meta’s - 51. N Queens

Gas Stations

Jump Game 2

Find First And Last Element In Sorted Array

Insert Search Position

Spiral Matrix

Combination Sum 2

Letter Combinations Of A Phone Number

Remove Nth Node From Linked List

Jump Game

Group Anagrams

Triangle

Happy Number

Palindromic Substrings

Google’s - 5. Longest Palindromic Substring

Amazon’s - 279. Perfect Squares

Longest Consecutive Sequence

Microsoft’s - 295. Find Median Of Data Stream

Lexicographical Numbers

Min Window Substring

Amazon’s - Max Product Subarray

Meta’s - Daily Temps

Prefix And Suffix Search

Meta’s - Set Matrix Zeroes

Amazon’s - Next Greater Element 1

Amazon’s - Next Greater Element 2

Meta’s - Search Words 2

Google’s - Sliding Window Maximum

Meta’s - Repeated DNA Sequences

Google’s - Design Add And Search Word Data Structure

Microsoft’s - Implement Trie

Google’s - Palindrome Partitioning

Google’s - Best Time To Buy And Sell Stock

Meta’s - Isomorphic Strings

K Diff Pairs In An Array

Max Enemy Forts That Can Be Captured

Boats To Save People

Amazon’s - Linked List Cycle Detection

Linked List Cycle 2

Google’s - Max Twin Sum Of Linked List

Amazon’s - Find Duplicate Number

Microsoft’s - Middle Of Linked List

Amazon’s - Subarray Sum Equals K

Microsoft’s - Find Pivot Index

Amazon’s - Range Query 2D

Amazon’s - Range Sum Query

Google’s - Trapping Rain

Microsoft’s - Remove Duplicates From Sorted Array

Google and Meta’s - Container With Most Water

Spotify’s - Valid Palindrome

Amazon’s - 2 Sum 2

Google’s - Longest Repeating Substring With Replacement

Amazon’s - Minimum Size Subarray

Fair Distribution Of Cookies

Amazon’s - Number Of Sub Arrays Of Size K And Average Greater Than Or Equal To Threshold

Meta’s - Contains Duplicates 2

Amazon’s - Longest Turbulent Subarray

Sum Of Power Of All Subsequences

Microsoft’s - Max Circular Subarray

Amazon’s - Max Subarray

Google’s - Longest Common Subsequence

Amazon’s - Min Stack

Amazon’s - Reverse Bits

Problem Statement in English Approach This is a subset of this problem. Solution in Python class Solution: def hammingWeight(self, n: int) -> int: ans = 0 while n > 0: if n&1 > 0: ans+=1 n = n >> 1 return ans Complexity Time: $O(1)$ Since we only process $32$ bits at most. Space: $O(1)$ Since we only store an integer variable. And we are done.

Amazon’s - Counting Bits

Meta’s - Sort Colors

Google’s - Unique Paths

Google’s - Unique Paths 2

Google’s - House Robber

Google’s - Course Schedule

Google’s - Clone Graph

Amazon’s - Shortest Path In Binary Matrix

Amazon’s - Rotting Oranges

Google’s - Number of Islands

Amazon’s - Product Of Array Except Self

Meta’s - Longest Substring Without Repeating Chars

Meta’s - Max Area of Island

Leetcode’s first problem

Twitch’s - LRU Cache

Microsoft’s Contains Duplicate

Google’s - Last Stone Weight

Microsoft’s - Kth Largest Element

Meta’s - K Closest Points

Meta’s - Partition Labels

Amazon’s - Combination Sum

Meta’s - Subsets

Microsoft’s - Path Sum

Amazon’s - Construct Binary Tree

Meta’s - Right Side View

Amazon’s - Kth Smallest Node In BST

Meta’s - Merge K Sorted Linked Lists

Amazon’s - Delete Node in BST

Amazon’s - Climbing Stairs

Microsoft’s - Search 2D Matrix

Google’s - ‘Koko Eating Bananas’