Grammarly Interview Questions

#1. Merge Intervals

This question is very likely to be asked in your Grammarly interview

You are given a collection of intervals. Merge all overlapping intervals into a single interval and return the result.

ArraysSorting

Remove All Adjacent Duplicates In String

You're given a string and need to repeatedly remove adjacent, identical characters until no more duplicates exist. Return the final string after all such removals.

StringsStacksTwo Pointers

Very likely

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#2. Remove All Adjacent Duplicates In String

StringsStacksTwo Pointers

You're given a string and need to repeatedly remove adjacent, identical characters until no more duplicates exist. Return the final string after all such removals.

This question is very likely to be asked in your Grammarly interview

Insert Delete GetRandom O(1)

Design a data structure that supports insert, delete, and getRandom operations, all in average O(1) time. The getRandom method should return a random element from the current set of elements.

ArraysHash Table

Very likely

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#3. Insert Delete GetRandom O(1)

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Design a data structure that supports insert, delete, and getRandom operations, all in average O(1) time. The getRandom method should return a random element from the current set of elements.

ArraysHash Table

Remove All Adjacent Duplicates in String II

Given a string, repeatedly remove consecutive duplicate characters if they appear k times in a row. The goal is to return the final string after all possible removals.

ArraysStacks

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#4. Remove All Adjacent Duplicates in String II

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Given a string, repeatedly remove consecutive duplicate characters if they appear k times in a row. The goal is to return the final string after all possible removals.

ArraysStacks

Vowel Spellchecker

Implement a spellchecker that corrects misspellings by considering both exact matches and variations where vowels may be incorrect or missing. Given a list of correctly spelled words (the wordlist) and a list of queries, return the corrected spelling for each query based on prioritized matching rules.

ArraysStrings

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#5. Vowel Spellchecker

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ArraysStrings

Repeated DNA Sequences

Find all the 10-letter long sequences that occur more than once in a given DNA molecule represented as a string. The DNA string contains only the characters 'A', 'C', 'G', and 'T'.

ArraysStringsSliding WindowsBit Manipulation

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#6. Repeated DNA Sequences

ArraysStringsSliding WindowsBit Manipulation

Find all the 10-letter long sequences that occur more than once in a given DNA molecule represented as a string. The DNA string contains only the characters 'A', 'C', 'G', and 'T'.

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Search in Rotated Sorted Array

You're given a sorted array that has been rotated, and a target value. Find the index of the target value in the rotated array, or return -1 if it's not present.

ArraysBinary Search

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#7. Search in Rotated Sorted Array

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You're given a sorted array that has been rotated, and a target value. Find the index of the target value in the rotated array, or return -1 if it's not present.

ArraysBinary Search

Generate Parentheses

Given a number 'n', generate all possible well-formed (balanced) parentheses strings of length 2*n. For instance, if n=3, you need to create all valid combinations like '((()))', '(()())', etc.

StringsRecursionBacktracking

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#8. Generate Parentheses

StringsRecursionBacktracking

Given a number 'n', generate all possible well-formed (balanced) parentheses strings of length 2*n. For instance, if n=3, you need to create all valid combinations like '((()))', '(()())', etc.

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Perfect Number

Determine if a positive integer is a perfect number. A perfect number equals the sum of its proper divisors (excluding the number itself).

ArraysTwo Pointers

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#9. Perfect Number

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Determine if a positive integer is a perfect number. A perfect number equals the sum of its proper divisors (excluding the number itself).

ArraysTwo Pointers

Climbing Stairs

You are climbing a staircase with n steps. Find how many distinct ways you can climb to the top, given that you can climb one or two steps at a time.

Dynamic Programming

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#10. Climbing Stairs

This question is somewhat likely to be asked in your Grammarly interview

You are climbing a staircase with n steps. Find how many distinct ways you can climb to the top, given that you can climb one or two steps at a time.

Dynamic Programming

Sqrt(x)

Calculate the integer square root of a non-negative integer, truncating any decimal portion. Return the integer part of the square root.

Binary Search

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#11. Sqrt(x)

This question is not likely to be asked in your Grammarly interview

Calculate the integer square root of a non-negative integer, truncating any decimal portion. Return the integer part of the square root.

Binary Search

Word Search

Determine if a given word can be constructed from letters in a 2D board, where letters can be used horizontally or vertically. Each letter can only be used once in the word.

ArraysRecursion

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#12. Word Search

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Determine if a given word can be constructed from letters in a 2D board, where letters can be used horizontally or vertically. Each letter can only be used once in the word.

ArraysRecursion

Number of Islands

Given a grid representing land and water, count the number of distinct islands. An island is formed by connected land cells.

ArraysGraphs

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#13. Number of Islands

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Given a grid representing land and water, count the number of distinct islands. An island is formed by connected land cells.

ArraysGraphs

Backspace String Compare

Simulate backspace operations on two strings and determine if the resulting strings are equal. Effectively, you need to compare strings after processing backspace characters.

StringsTwo PointersStacks

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#14. Backspace String Compare

StringsTwo PointersStacks

Simulate backspace operations on two strings and determine if the resulting strings are equal. Effectively, you need to compare strings after processing backspace characters.

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Word Break II

Given a string and a dictionary of words, find all possible ways to break the string into space-separated words from the dictionary. Return the list of these valid sentences.

StringsArraysDynamic ProgrammingRecursion

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Hard

#15. Word Break II

Hard

Given a string and a dictionary of words, find all possible ways to break the string into space-separated words from the dictionary. Return the list of these valid sentences.

StringsArraysDynamic ProgrammingRecursion

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Sum of Left Leaves

Find the sum of all the left leaves in a given binary tree. A left leaf is a node that is both a leaf and the left child of its parent.

TreesRecursion

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#16. Sum of Left Leaves

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Find the sum of all the left leaves in a given binary tree. A left leaf is a node that is both a leaf and the left child of its parent.

TreesRecursion

Implement Trie (Prefix Tree)

Design a data structure that efficiently stores a set of strings and allows for prefix-based searches. Implement methods to insert strings, search for complete words, and check if any word starts with a given prefix.

StringsTrees

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#17. Implement Trie (Prefix Tree)

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StringsTrees

Logger Rate Limiter

Design a logger that prevents duplicate messages from being printed within a certain time window. Determine if a message should be printed based on its timestamp and content, considering rate limiting.

ArraysTwo PointersSliding Windows

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#18. Logger Rate Limiter

ArraysTwo PointersSliding Windows

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Word Break

Determine if a given string can be segmented into a space-separated sequence of words from a dictionary. You are given a string and a dictionary of words; can you break the string down using words from the dictionary?

ArraysStringsDynamic Programming

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#19. Word Break