# Questions tagged [interview-questions]

This tag is for questions that came up in an interview.

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### Find the highest result between two elements in an array using their values and indices

I got a programming question on an interview where performance was the focus. I couldnt come up with a better solution than the one below which I think has a time complexity of O(n^2 + n) and scored ...
83 views

### Find first repeating Char in String

Given a string, find the first repeating character in it. Examples: firstUnique("Vikrant")None ...
46 views

### Expand spreadsheet ranges to lists of cells in Scala

Problem Spreadsheet cells are referenced by column and row identifiers. Columns are labeled with alphabetical characters, starting with "A", "B", "C", ...; rows are numbered from 1 in ascending ...
89 views

### Minimum steps to reach target by a Knight In Scala

Given a chessboard of N size (square matrix), the position of Knight and position of a target, find out minimum steps (both count and exact steps) from start to target for a Knight. If it is not ...
435 views

### LeetCode 189 - Rotate Array

I have a working solution for this problem that was accepted in LeetCode: Given an array, rotate the array to the right by k steps, where k is non-negative." ...
65 views

### Closest 3Sum in Scala

This question is taken from Leet code. Given an array nums of n integers and an integer target, find three integers in nums such that the sum is closest to target. Return the sum of the three ...
78 views

### Replace array element with multiplication of neighbors in Scala

Given an array of integers, update the index with multiplication of previous and next integers, Input: 2 , 3, 4, 5, 6 Output: 2*3, 2*4, 3*5, 4*6, 5*6 Following ...
240 views

### Clockwise rotate a matrix in Scala

Given a matrix, clockwise rotate elements in it. Examples: ...
165 views

### Print matrix in spiral order in Scala

Problem: Given a square or rectangular matrix, print its element in spiral order. For example, if input matrix is this: ...
146 views

### Print words in decreasing order of frequency in Scala

Given a string print its words in decreasing order of frequency. Example: i/p - "aa bbb ccc aa ddd aa ccc" o/p - aa,ccc,ddd,bbb Scala: ...
77 views

### List of Happy Numbers in scala

Definition of Happy numbers taken from Wikipedia. A happy number is defined by the following process: Starting with any positive integer, replace the number by the sum of the squares of its digits ...
1k views

### Calculate the score of a bowling game

Before a job interview, I was asked to create a program that can calculate the score of a bowling game. The full assignment and my code can be viewed on my Github. The company told me that this was ...
211 views

### Function to return subword of a camelcase string

Given a camelcase string and an index, return the subword of the string that includes that index, e.g.: ...
73 views

### Custom indexOf for strings javascript with regex

I was wondering how efficient my code is creating custom indexOf for strings in JavaScript using regex instead of looping with a for statement the whole way in most ...
64 views

### Implementing key map with expire and size limit

Recently I have been asked to implement a key map with expire time for each key and possibility to limit the number of keys, in Python. I've used a dictionary + heap to store the entries, e.g.: ...
207 views

### Calculate simple arithmetic string in Scala

Problem Given an arithmetic string like 2+2*3 calculate result 8. Assumptions you can make string will be always well formed (no error checking needs to be done) only operators passed in string ...
130 views

### Symfony controller to register and activate users

I've been in an interview some time ago. They objected my Symfony API code with following line: Too much code in controller actions. Can be moved to services to keep the business logic apart ...
65 views

### find if one string is a valid anagram of another , in scala

Question is taken from leet code. Problem Given two strings s and t , write a function to determine if t is an anagram of s. Examples ...
241 views

### Longest Substring Without Repeating Characters in Scala

Question is taken from Leetcode and solution works for their test cases. I do see a scope of improvement and make it more functional (getting rid of vars and mutables data structures). Please suggest ...
182 views

### Find kth smallest element in binary search tree

I was faced with below interview question today and I came up with below solution but somehow interviewer was not happy. I am not sure why.. Given a binary search tree, find the kth smallest ...
82 views

### Expressing positive integers as the sum of different charming numbers

In a practice academic interview of mine, we discussed question six, round one, of the United Kingdom Mathematics Trust's 2015 British Mathematical Olympiad. Which states: A positive integer is ...
115 views

### Hashing interview puzzle

I've stumbled upon this pretty old article about a hashing interview question, and here it is converted to Swift in a more generic way: ...
2k views

### Find the smallest positive number missing from an unsorted array

this is the original question https://www.geeksforgeeks.org/find-the-smallest-positive-number-missing-from-an-unsorted-array/ You are given an unsorted array with both positive and negative elements....
85 views

### Map Character to Characters Most Frequently Found With it (in list of strings)

For an interview, I was tasked with writing a program that consumes a list of strings, and produces a mapping between every character in the list, and the characters found most frequently with it (let'...
312 views

### String Compression

Implement a method to perform basic string compression using the counts of repeated characters. For example, the string "aabcccccaaa" would become "a2b1c5a3". If the "compressed" string ...
5k views

### Find the shortest path between two points in a 2D matrix with obstacles

I need to find shortest path between two points in a grid given an obstacles.. Given a 2 dimensional matrix where some of the elements are filled with 1 and rest of the elements are filled. Here ...
908 views

### String Encoder with lower-case output

Question: Take an input string and output the "encoded" string by using the following rules: ...
143 views

### HashMap implementation, is this good enough for interviews?

After understanding HashMaps, I decided to implement my own using 3 classes HashMap, LinkedList, and Node. I knew how to implement LinkedList from before. Can you please give me feedback on this. ...
110 views

### Find contiguous integers with a given sum

Introduction This question was asked in a technical interview, I am looking for some feedback on my solution. Given a list of integers and a number K, return which contiguous elements of the list ...
63 views

### Leetcode #826. Most Profit Assigning Work solution in Java (Sort + Binary Search)

Problem Statement: We have jobs: difficulty[i] is the difficulty of the ith job, and profit[i] is the profit of the ith job....
55 views

### Check if list contains a pair which adds up to a given sum

Kindly review this scala code for given problem and suggest improvements. Problem - Given an array of integers and a target sum, check if array contains a pair which adds up to sum. Example - <...
56 views

### Design a system for renting digital movies/books

During an interview I was asked to do an OO design for a digital renting system for books/movies. This is the design that I came up with. My assumptions: When the customer has downloaded a list of ...
185 views

### Balanced parenthesis, with backslash escaping

Given a Balanced Parenthesis problem. "Balanced Parenthesis Create a program that checks if in a given string expression all the parenthesis are balanced. For Example: (test) - valid ...
66 views

### Given an integer number, invert its bits. You cannot use the ~ operator

Here is my code: ...
127 views

### Simple recursive transformation solution in Python

This simple Python code I wrote for a problem asked during an interview. The problem statement is: Given a tuple (a, b), transform this into (c, d) by applying any of the two below operations ...
224 views

### Top K frequent elements

I am working on an interview question where I need to return the k most frequent elements given a non-empty array of integers. Input: nums = [1,1,1,2,2,3], k = 2 Output: [1,2] Here is my code: <...
268 views

### Leetcode #146. LRUCache solution in Java (Doubly Linked List + HashMap)

Problem Statement Design and implement a data structure for Least Recently Used (LRU) cache. It should support the following operations: get and put. get(key) - Get the value (will always be ...
57 views

### Find the combination of matches which are closest to each other

Problem - Given three sorted arrays find combinations which are closest to each other. example - ...
256 views

### Find maximum in sorted and rotated array

This is an interview question. A sorted rotated array is a sorted array which was rotated 0 or more times. For example: [1,2,3] -> [2,3,1] ...
167 views

### Design a system for creating a coffeeshop menu

During an interview I was asked to design the menu for a coffee shop employee so that the employee would go and add different items to the menu. This is the design that I came up with. I just want ...
70 views

### Mark positions attacked by a queen on a chess board

Problem - Given a chess board and the position of only one queen piece in it, mark all the position where the queen can move with X. Kindly review this Scala code and suggest improvements. ...
271 views

### Whiteboarding - Multiply all values in array except at the index for each

Consider this interview question: You have an array of integers, and for each index you want to find the product of every integer except the integer at that index. Write a method ...
495 views

### Converting employee survey data from CSV to JSON

This Java code project was submitted for a job opportunity but was marked down for showing "bad habits that could be difficult to unlearn" but I am mystified by what this means. Any takers please. How ...
96 views

### Determine a list contains two elements with a given sum

On interview I was asked to write method with following contract: boolean checkList(List<Long> list, long sum){...} for example it has to return true for ...
2k views

### Print odd and even numbers using two threads in Java

I was asked below question in an interview where I need to print out even and odd numbers using two threads so I came up with below code one without synchronization and other with synchronization. <...
139 views

### Exercise to refactor a class with various credit limit rules

I recently did a programming exercise for a company which I didn't pass. I didn't get any good feedback from my test so I wanted some advice/opinions for what I did wrong and what I could have done ...
2k views

### Check if a string is a valid english word, and convert to a valid english word

This is an interview question. For the purpose of the question, a valid English word is a string that begins with an uppercase English letter, and the rest of the string contains only lowercase ...
653 views

### Binomial coefficient in Java

Find nCr for given n and r. Input: First line contains no of test cases T, for every test case 2 integers as inputs (n,r). Output: Compute and print the value in separate line. ...