Grammarly Coding Interview Questions

Merge Intervals

Given an array of intervals where intervals[i] = [starti, endi], merge all overlapping intervals, and return an array of the non-overlapping intervals that cove...

Remove All Adjacent Duplicates In String

You are given a string s consisting of lowercase English letters. A duplicate removal consists of choosing two adjacent and equal letters and removing them.

Remove All Adjacent Duplicates in String II

You are given a string s and an integer k, a k duplicate removal consists of choosing k adjacent and equal letters from s and removing them, causing the left an...

Insert Delete GetRandom O(1)

Implement the RandomizedSet class:

Generate Parentheses

Given n pairs of parentheses, write a function to generate all combinations of well-formed parentheses.

Vowel Spellchecker

Given a wordlist, we want to implement a spellchecker that converts a query word into a correct word.

Repeated DNA Sequences

The DNA sequence is composed of a series of nucleotides abbreviated as 'A', 'C', 'G', and 'T'.

Search in Rotated Sorted Array

There is an integer array nums sorted in ascending order (with distinct values).

Perfect Number

A perfect number is a positive integer that is equal to the sum of its positive divisors, excluding the number itself. A divisor of an integer x is an integer t...

Climbing Stairs

You are climbing a staircase. It takes n steps to reach the top.

Sqrt(x)

Given a non-negative integer x, return the square root of x rounded down to the nearest integer. The returned integer should be non-negative as well.

Number of Islands

Given an m x n 2D binary grid grid which represents a map of '1's (land) and '0's (water), return the number of islands.

Word Search

Given an m x n grid of characters board and a string word, return true if word exists in the grid.

Word Break II

Given a string s and a dictionary of strings wordDict, add spaces in s to construct a sentence where each word is a valid dictionary word. Return all such possi...

Backspace String Compare

Given two strings s and t, return true if they are equal when both are typed into empty text editors. '' means a backspace character.

Implement Trie (Prefix Tree)

A trie (pronounced as "try") or prefix tree is a tree data structure used to efficiently store and retrieve keys in a dataset of strings. There are various appl...

Word Break

Given a string s and a dictionary of strings wordDict, return true if s can be segmented into a space-separated sequence of one or more dictionary words.

Special Binary String

Special binary strings are binary strings with the following two properties:

Clone Graph

Given a reference of a node in a connected undirected graph.

Evaluate Reverse Polish Notation

You are given an array of strings tokens that represents an arithmetic expression in a Reverse Polish Notation.

Trapping Rain Water

Given n non-negative integers representing an elevation map where the width of each bar is 1, compute how much water it can trap after raining.

Unique Paths

There is a robot on an m x n grid. The robot is initially located at the top-left corner (i.e., grid[0][0]). The robot tries to move to the bottom-right corner...

Decode the Slanted Ciphertext

A string originalText is encoded using a slanted transposition cipher to a string encodedText with the help of a matrix having a fixed number of rows rows.

Sum of Left Leaves

Given the root of a binary tree, return the sum of all left leaves.

Set Mismatch

You have a set of integers s, which originally contains all the numbers from 1 to n. Unfortunately, due to some error, one of the numbers in s got duplicated to...

Maximum Palindromes After Operations

You are given a 0-indexed string array words having length n and containing 0-indexed strings.