Microsoft Coding Interview Questions: 190 Tagged Problems

Microsoft study plan by topic

40 of the 190 problems tagged Microsoft over 4 weeks, about 21 h 5 min of solving, grouped by technique in the order they build on each other — Strings, Hash Table, Counting and Math and 24 more. It ends with the Microsoft — Online Assessment mock.

Week 1: Strings, Hash Table, Counting +5

12 problems on Strings, Hash Table, Counting, Math, Two Pointers, Sliding Window, Prefix Sum and Sorting, easiest first within each topic.

• Length of Last Word Easy
• Roman to Integer Easy
• Maximum Count of Positive Integer and Negative Integer Easy
• Reverse Integer Medium
• Reverse String Easy
• String Compression Medium
• Longest Subarray of 1's After Deleting One Element Medium
• Maximum Number of Occurrences of a Substring Medium
• Running Sum of 1d Array Easy
• Left and Right Sum Differences Easy
• Minimum Deletions to Make Character Frequencies Unique Medium
• Remove Covered Intervals Medium

Week 2: Counting Sort, Binary Search, Stack +5

12 problems on Counting Sort, Binary Search, Stack, Queue, Monotonic Stack, Matrix, Simulation and Greedy, easiest first within each topic.

• Height Checker Easy
• Count Negative Numbers in a Sorted Matrix Easy
• Longest Valid Parentheses Hard
• First Unique Character in a String Easy
• Maximal Rectangle Hard
• Unique Paths II Medium
• Minimum Path Sum Medium
• Build Array from Permutation Easy
• Game of Life Medium
• Count and Say Medium
• Can Place Flowers Easy
• Integer to Roman Medium

Week 3: Recursion, Divide and Conquer, Quickselect +8

12 problems on Recursion, Divide and Conquer, Quickselect, Heap, Bit Manipulation, Bitmask, Backtracking, Graph, Breadth-First Search, Union Find and Shortest Path, easiest first within each topic.

• Power of Four Easy
• Number of 1 Bits Easy
• K Closest Points to Origin Medium
• The K Weakest Rows in a Matrix Easy
• Ugly Number II Medium
• Sum of Two Integers Medium
• Minimum Number of Work Sessions to Finish the Tasks Medium
• Word Search Medium
• Keys and Rooms Medium
• Word Ladder Hard
• Surrounded Regions Medium
• Number of Restricted Paths From First to Last Node Hard

Week 4: Dynamic Programming

4 problems on Dynamic Programming, easiest first.

• Delete Operation for Two Strings Medium
• Interleaving String Medium
• Last Stone Weight II Medium
• Best Time to Buy and Sell Stock III Hard

Finally: the timed test

Sit the Microsoft — Online Assessment mock under the clock — the coding problems are only one part of the round.

Take the Microsoft — Online Assessment mock

Microsoft test patterns

• Microsoft — Online Assessment pattern guide and timed mock

All problems tagged Microsoft

Easy (45)

• Determine the Winner of a Bowling Game Array, Simulation
• Minimum Moves to Convert String String, Greedy
• Take Gifts From the Richest Pile Array, Heap, Simulation
• Sqrt(x) Math, Binary Search
• Find Smallest Letter Greater Than Target Array, Binary Search
• Count Subarrays of Length Three With a Condition Array, Sliding Window
• Defuse the Bomb Array, Sliding Window, Simulation
• Maximum Sum Subarray of Size K Array, Sliding Window
• Add to Array-Form of Integer Array, Math
• Longest Nice Substring String, Divide and Conquer
• Greatest Common Divisor of Strings String, Math
• Minimum Operations to Make the Array Increasing Array, Greedy
• Minimum Value to Get Positive Step by Step Sum Array, Prefix Sum
• Convert a Number to Hexadecimal Math, Bit Manipulation
• Power of Four Math, Bit Manipulation, Recursion
• Number of 1 Bits Divide and Conquer, Bit Manipulation
• Sort Even and Odd Indices Independently Array, Sorting
• Special Positions in a Binary Matrix Array, Matrix
• Find Winner on a Tic Tac Toe Game Array, Hash Table, Matrix
• Convert 1D Array Into 2D Array Array, Matrix, Simulation
• Row With Maximum Ones Array, Matrix
• The K Weakest Rows in a Matrix Array, Binary Search, Sorting
• Shift 2D Grid Array, Matrix, Simulation
• Count Negative Numbers in a Sorted Matrix Array, Binary Search, Matrix
• Reshape the Matrix Array, Matrix, Simulation
• Maximum Count of Positive Integer and Negative Integer Array, Binary Search, Counting
• Left and Right Sum Differences Array, Prefix Sum
• Remove Element Array, Two Pointers
• Check If Two String Arrays Are Equivalent Array, String
• Unique Email Addresses Array, Hash Table, String
• Rotate String String, String Matching
• Shuffle String Array, String
• Repeated Substring Pattern String, String Matching
• Length of Last Word String
• First Unique Character in a String Hash Table, String, Queue
• Relative Sort Array Array, Hash Table, Sorting
• Height Checker Array, Sorting, Counting Sort
• Can Place Flowers Array, Greedy
• Max Consecutive Ones Array
• Build Array from Permutation Array, Simulation
• Running Sum of 1d Array Array, Prefix Sum
• Roman to Integer Hash Table, Math, String
• Excel Sheet Column Title Math, String
• Excel Sheet Column Number Math, String
• Reverse String Two Pointers, String

Medium (90)

• Find the Winner of an Array Game Array, Simulation
• Find the Winner of the Circular Game Array, Math, Recursion
• Stone Game VII Array, Math, Dynamic Programming
• Minimum Number of Work Sessions to Finish the Tasks Array, Dynamic Programming, Bit Manipulation
• Count Fertile Pyramids in a Land Array, Dynamic Programming, Matrix
• Number of Ways to Divide a Long Corridor Math, String, Dynamic Programming
• Construct String With Repeat Limit Hash Table, String, Greedy
• Minimum Number of Changes to Make Binary String Beautiful String, Greedy
• Alternating Groups II Array, Sliding Window
• Maximum Value of an Ordered Triplet II Array, Prefix Sum
• Process Tasks Using Servers Array, Simulation, Heap (Priority Queue)
• Number of Ways to Arrive at Destination Graph, Dynamic Programming, Shortest Path
• Shortest Path with Alternating Colors Graph, Breadth-First Search
• Maximum Number of Fish in a Grid Array, Matrix, Depth-First Search
• Map of Highest Peak Array, Matrix, Breadth-First Search
• Convert an Array Into a 2D Array With Conditions Array, Matrix, Hash Table
• Rotating the Box Array, Matrix, Two Pointers
• Difference Between Ones and Zeros in Row and Column Array, Matrix, Simulation
• Count Alternating Subarrays Array, Math, Dynamic Programming
• Maximum Consecutive Floors Without Special Floors Array, Sorting, Greedy
• Removing Minimum and Maximum From Array Array, Greedy
• Search a 2D Matrix II Array, Matrix, Binary Search
• Find First and Last Position of Element in Sorted Array Array, Binary Search
• Minimum Consecutive Cards to Pick Up Array, Hash Table, Sliding Window
• Count Complete Subarrays in an Array Array, Hash Table, Sliding Window
• K Radius Subarray Averages Array, Sliding Window, Prefix Sum
• The k Strongest Values in an Array Array, Two Pointers, Sorting
• Super Ugly Number Dynamic Programming, Math, Heap
• Minimum Operations to Reduce an Integer to 0 Bit Manipulation, Greedy, Dynamic Programming
• 4Sum II Hash Table, Array, Counting
• Maximum Size Subarray Sum Equals k Array, Hash Table, Prefix Sum
• Maximum Number of Occurrences of a Substring String, Sliding Window, Hash Table
• Kth Smallest Element Array, Sorting, Quickselect
• Maximum Index Array, Two Pointers
• Count Inversions Array, Divide and Conquer, Fenwick Tree
• K-diff Pairs in an Array Array, Hash Table
• Word Search Array, String, Backtracking
• Snakes and Ladders Array, Breadth-First Search, Matrix
• Minimum Genetic Mutation Hash Table, String, Breadth-First Search
• Maximal Network Rank Graph
• Path With Minimum Effort Array, Binary Search, Depth-First Search
• Time Needed to Inform All Employees Tree, Depth-First Search, Breadth-First Search
• Reorder Routes to Make All Paths Lead to the City Zero Depth-First Search, Breadth-First Search, Graph
• Number of Operations to Make Network Connected Depth-First Search, Breadth-First Search, Union Find
• Find Eventual Safe States Depth-First Search, Breadth-First Search, Graph
• Keys and Rooms Depth-First Search, Breadth-First Search, Graph
• Bulb Switcher Math, Brainteaser
• Divide Two Integers Math, Bit Manipulation
• Gray Code Math, Backtracking, Bit Manipulation
• Maximum XOR of Two Numbers in an Array Array, Hash Table, Bit Manipulation
• Sum of Two Integers Math, Bit Manipulation
• Bitwise AND of Numbers Range Bit Manipulation
• Single Number II Array, Bit Manipulation
• Dota2 Senate String, Greedy, Queue
• Reverse Substrings Between Each Pair of Parentheses String, Stack
• Basic Calculator II Math, String, Stack
• Validate Stack Sequences Array, Stack, Simulation
• Next Greater Element III Math, Two Pointers, String
• K Closest Points to Origin Array, Math, Divide and Conquer
• Partition Array into Disjoint Intervals Array, Greedy
• Maximum Swap Math, Greedy
• Largest Number Array, String, Greedy
• Remove Covered Intervals Array, Greedy, Sorting
• Minimum Number of Steps to Make Two Strings Anagram Hash Table, String, Counting
• Minimum Deletions to Make Character Frequencies Unique String, Hash Table, Greedy
• Reduce Array Size to The Half Array, Hash Table, Greedy
• Queue Reconstruction by Height Array, Greedy, Sorting
• Knight Dialer Dynamic Programming
• Last Stone Weight II Array, Dynamic Programming
• Ugly Number II Hash Table, Math, Dynamic Programming
• Interleaving String String, Dynamic Programming
• Delete Operation for Two Strings String, Dynamic Programming
• Count Servers that Communicate Array, Depth-First Search, Breadth-First Search
• Surrounded Regions Array, Depth-First Search, Breadth-First Search
• Game of Life Array, Matrix, Simulation
• Unique Paths II Array, Dynamic Programming, Matrix
• Minimum Path Sum Array, Dynamic Programming, Matrix
• Sort the Matrix Diagonally Array, Sorting, Matrix
• Spiral Matrix II Array, Matrix, Simulation
• Remove Duplicates from Sorted Array II Array, Two Pointers
• Longest Subarray of 1's After Deleting One Element Array, Dynamic Programming, Sliding Window
• String Compression Two Pointers, String
• Count and Say String, Simulation
• Reverse Words in a String Two Pointers, String
• Increasing Triplet Subsequence Array, Greedy
• Next Permutation Array, Two Pointers
• Find All Duplicates in an Array Array, Hash Table
• Integer to Roman Hash Table, Math, String
• Count Primes Math, Sieve of Eratosthenes
• Reverse Integer Math

Hard (55)

• Count Ways to Make Array With Product Array, Math, Dynamic Programming
• Maximum Number of Events That Can Be Attended II Array, Binary Search, Dynamic Programming
• Create Sorted Array Through Instructions Array, Binary Search, Divide and Conquer
• Painting the Walls Array, Dynamic Programming
• Painting a Grid With Three Different Colors Dynamic Programming, Bitmask
• Minimum Incompatibility Array, Dynamic Programming, Bit Manipulation
• Number of Distinct Roll Sequences Dynamic Programming, Memoization
• Form Largest Integer With Digits That Add up to Target Array, String, Dynamic Programming
• Build Array Where You Can Find The Maximum Exactly K Comparisons Dynamic Programming, Prefix Sum
• Allocate Mailboxes Array, Math, Dynamic Programming
• Restore the Array String, Dynamic Programming
• Maximum Height by Stacking Cuboids Array, Dynamic Programming, Sorting
• Cherry Pickup II Array, Dynamic Programming, Matrix
• Number of Ways to Stay in the Same Place After Some Steps Dynamic Programming
• Maximum Value of K Coins From Piles Array, Dynamic Programming, Prefix Sum
• Count Special Integers Math, Dynamic Programming, Combinatorics
• Number of Great Partitions Array, Dynamic Programming
• Paths in Matrix Whose Sum Is Divisible by K Array, Dynamic Programming, Matrix
• Smallest K-Length Subsequence With Occurrences of a Letter String, Stack, Greedy
• Valid Palindrome III String, Dynamic Programming
• String Compression II String, Dynamic Programming
• Apply Operations to Maximize Score Array, Math, Stack
• Meeting Rooms III Array, Sorting, Simulation
• Maximum Performance of a Team Array, Greedy, Sorting
• Construct Target Array With Multiple Sums Array, Heap (Priority Queue), Math
• Minimum Number of Operations to Make Array Continuous Array, Hash Table, Binary Search
• Put Marbles in Bags Array, Greedy, Sorting
• Minimum Time to Visit a Cell In a Grid Array, Matrix, Graph
• Minimum Number of Days to Disconnect Island Array, Matrix, Depth-First Search
• Checking Existence of Edge Length Limited Paths Array, Union Find, Graph
• Minimum Obstacle Removal to Reach Corner Array, Matrix, Graph
• Largest Component Size by Common Factor Array, Math, Union Find
• Critical Connections in a Network Graph, Depth-First Search, Biconnected Component
• Number of Restricted Paths From First to Last Node Graph, Dynamic Programming, Shortest Path
• Jump Game IV Array, Hash Table, Breadth-First Search
• Escape the Spreading Fire Array, Matrix, Binary Search
• Making A Large Island Array, Matrix, Depth-First Search
• Unique Paths III Array, Matrix, Backtracking
• Maximal Rectangle Array, Matrix, Stack
• Minimum Cost to Cut a Stick Array, Dynamic Programming, Sorting
• Scramble String String, Dynamic Programming
• Distinct Subsequences II String, Dynamic Programming
• Frog Jump Array, Hash Table, Dynamic Programming
• Dungeon Game Array, Matrix, Dynamic Programming
• Russian Doll Envelopes Array, Binary Search, Dynamic Programming
• Split Array Largest Sum Array, Binary Search, Greedy
• Shortest Subarray with Sum at Least K Array, Prefix Sum, Sliding Window
• Subarrays with K Different Integers Array, Hash Table, Sliding Window
• Number of Digit One Math, Digit DP, Recursion
• Longest Happy Prefix String, KMP, Rolling Hash
• Shortest Palindrome String, KMP, Rolling Hash
• Word Ladder Hash Table, String, Breadth-First Search
• Longest Valid Parentheses String, Dynamic Programming, Stack
• Count Vowels Permutation Dynamic Programming
• Best Time to Buy and Sell Stock III Array, Dynamic Programming

Topics Microsoft asks most

• Arrays 119 problems
• Dynamic Programming 47 problems
• Strings 44 problems
• Matrix 35 problems
• Math 32 problems
• Hash Table 26 problems
• Sorting 24 problems
• Greedy 24 problems
• Breadth-First Search 20 problems
• Simulation 18 problems
• Heap 16 problems
• Binary Search 15 problems

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