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Questions tagged [interview-questions]

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

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40 votes
4 answers
7k views

Rainfall challenge

About a year ago when I was applying to jobs for the first time, I had an interview at a company and they posed the following problem to me, which I preceded to bomb. A year later I actually came up ...
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7 votes
1 answer
2k views

Swap items of a linked list in pairs

Here is the source of the question: GitHub Given a singly linked list, swap the list items in pairs (reconnect the pointers, not simply swap the values). For example: Before: A->B->C->D ...
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42 votes
5 answers
36k views

Designing a coffee machine

I was recently rejected from what looked like a really promising string of interviews. I did very well in a questionnaire style review, and then they handed me this assignment (more or less): ...
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22 votes
4 answers
6k views

Determining if an answer can be generated

How can I improve my code below for the following question? While it works, I am not satisfied with how it looks; I was hoping I can somehow keep it recursive, and have the ans filled up inside the ...
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  • 2,216
6 votes
5 answers
7k views

Validate that brackets are balanced

I've done a test for a job (which I failed) and I'd like to know in which ways my code could've been better. Here are the questions and my answers, it's not very long. 1) Make a program that ...
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21 votes
4 answers
2k views

Finding the sub-array with the maximum sum - my approach

This is the code I ended up with that implements the approach I described in a recent answer to another question about the same problem The basic idea here is to not loop through more things than ...
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3 votes
1 answer
150 views

Swap items of a linked list in pairs - revision 2

The first revision is available here and the code is available on GitHub. I modified the method reversePairs and added mSize to ...
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2 votes
1 answer
75 views

Swap items of a linked list in pairs - revision 3

Here is the source of the question. Revision 1. Revision 2. When I started the second round of code review, I wanted to make sure that I had included all the possible input types. However, I ...
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216 votes
4 answers
23k views

Calculate SHA1 hash from binary and verify with a provided hash

I applied for a job and they asked me to write code with the following requirements: Get a "toolbar offer" description from http..update.utorrent.com/installoffer.php?offer=conduit. Parse the ...
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  • 2,149
59 votes
11 answers
13k views

Sales tax calculator, rejected for being not OOP

I applied for an Application Developer position. They require all their applicants to complete 1 of 3 programming assignments. I picked one for sales tax calculation. It was quite simple. Write ...
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  • 607
39 votes
10 answers
9k views

Which FizzBuzz is better, and why?

I was in an interview and the guy asked me to do the typical FizzBuzz question of printing numbers 1-100, but for each factor of 3 print Fizz, each factor of 5 print Buzz, and each factor of both ...
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10 votes
2 answers
2k views

Missing level of technical depth (Common Ancestor)

I recently have given a coding test in a reputable IT company. There were three coding questions. They refused me by saying that as we felt they didn't demonstrate the level of technical depth we'...
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  • 419
20 votes
3 answers
4k views

Reversing k-sized sequences in a linked-list

Here is my solution to this problem; please be brutally honest/strict, if I would have written this code, in a 45 minute interview, what would you think? (I am aiming for Google,Facebook). Here is ...
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  • 2,216
6 votes
3 answers
2k views

Missing level of technical depth (Flatten Tree)

I recently have given a coding test in a reputable IT company. There were three coding questions. They refused me by saying that as we felt they didn't demonstrate the level of technical depth we'...
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  • 419
6 votes
1 answer
1k views

Missing level of technical depth (Recursive to Iterative)

I recently have given a coding test in a reputable IT company. There were three coding questions. They refused me by saying that as we felt they didn't demonstrate the level of technical depth we'...
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  • 419
5 votes
4 answers
290 views

Product of all but one number in a sequence - Follow Up

This question is a follow up question to the Product of all but one number in a sequence. I am posting a new code here with taking into consideration the suggestions of [Edward], [CiaPan], [chux], [...
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8 votes
1 answer
716 views

Are AVL trees equal?

I was inspired by this answer and decided to implement an AVL tree with the methods equals and hashCode as if I was asked to do ...
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6 votes
5 answers
805 views

DP solution to min triangle path

I am studying for interviews for various companies. I wrote a solution to this problem, but if an experience programmer looks at it I am sure there are certain areas the code can be made in to a more ...
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4 votes
1 answer
548 views

Improving time complexity of finding the longest palindrome in Python

The Longest Palindromic Substring challenge from InterviewBit: Given a string S, find the longest palindromic substring in S. where a "substring" must be contiguous, and in case of ties ...
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2 votes
3 answers
3k views

Find all triplets in array that add up to a given sum

Given an array and a value, find all the triplets in the array whose sum is equal to the given value. For example, if the given array is {12, 3, 4, 1, 6, 9} and the ...
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  • 345
1 vote
1 answer
90 views

Swap items of a linked list in pairs - revision 4

Here is the source of the question. The solution on GitHub. Revision 1. Revision 2. Revision 3. @200_success' suggestions from revision 3: The iterator's ...
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96 votes
16 answers
9k views

Outputting the names of cars, without repetitions, with the number of occurrences in order of decreasing repetitions

A short while ago, I have submitted a coding exercise to a potential employer. The response came back the next morning and you can guess what it was from the subject of this post. I am not ...
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151 votes
20 answers
31k views

Searching an element in a sorted array

I was applying for a position, and they asked me to complete a coding problem for them. I did so and submitted it, but I later found out I was rejected from the position. Anyways, I have an eclectic ...
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30 votes
8 answers
49k views

Find all the missing number(s)

Recently I've attended an interview, where I faced the below question: Question: "There is an sorted array. You need to find all the missing numbers. Write the complete code, without using any ...
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25 votes
7 answers
5k views

Sales Tax Problem, rejected for not being up to their standards

I applied for a Junior .NET Developer Position recently, and I was asked to solve a problem (Sales Tax Program) and I was rejected for some reason. The question goes like this: Basic sales tax is ...
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32 votes
3 answers
42k views

Overlapping rectangles

I received the following question in a technical interview today (for a devops/SRE position): Write a function which returns true if the two rectangles passed to it as arguments would overlap if ...
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16 votes
4 answers
78k views

FizzBuzz implementation

The common FizzBuzz implementation I saw is using a check for % 15 for printing "FizzBuzz" Would you let me know if there is anything wrong / better with this approach? ...
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12 votes
10 answers
7k views

Tests for palindromes in C and C++

A question I've been asked on interactive phone screens is to code a test to determine whether a string is a palindrome or not. I am providing two examples here: one in C and one in C++. They both ...
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  • 18.3k
8 votes
3 answers
2k views

Reorder a list of courses, given their prerequisites

I recently graduated from college and applied for a position with a company. I was sent a coding exercise as part of the process. After completing the exercise and submitting it I was told that the ...
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20 votes
2 answers
5k views

Designing another Coffee Machine Application

After reading Designing a coffee machine yesterday, I decided I could also give the same problem a try. I have used the following problem statement (copied from the given question): Design a ...
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  • 10.6k
17 votes
5 answers
25k views

Longest palindrome in a string

Please be brutal, and judge my code as if it was written at a top 3 tech company, straight out of college. (The method signature, and input parameter is given by the problem, so don't worry about that)...
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  • 2,216
13 votes
3 answers
881 views

Reversing a linked list

I implemented reversing a linked list in iterative way, just by knowing we need 3 pointers and I have never seen a code before, when I coded. I ran this code and tested it, it works fine. Even for ...
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13 votes
3 answers
18k views

Counting permutations without repetitions for a number or a string

Can I make the following code faster with minor modifications? It times out on CodeWars website. ...
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10 votes
2 answers
14k views

Add one to a number represented as an array of digits

I submitted this problem for an interview, and I was wondering if I could have done better. My solution works, and I solved in about 12-15 minutes. I feel like I did a bad job with the code. Please ...
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  • 2,216
14 votes
1 answer
10k views

Printing a Binary Tree top-down (column wise)

We have a binary tree, suppose like this: 8 / \ 6 10 / \ / \ 4 7 9 12 / \ 3 5 We have to print this binary tree in top-down ...
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11 votes
2 answers
4k views

Fizz Buzz interview question code

Reading Jeff Atwood's "Why Can't Programmers.. Program?" led me to think that almost all of the solutions would not be something I would want in my own code-base. The Fizz Buzz program specification ...
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  • 3,961
8 votes
3 answers
3k views

Elevator Interview Problem OOP - Revised

Elevator program code challenge, revised: Can someone please critique my Elevator problem - I wanted to use OOP principles and coding standards. Also, does logic make sense? ...
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8 votes
4 answers
16k views

Find the subarray with the max sum

In an interview I was asked to solve the following problem: find a subarray with max sum I have written a piece of code for the same. I need your help in reviewing this code. ...
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  • 183
6 votes
2 answers
858 views

XOR linked list implementation

I am trying to resolve below question in order to prepare for an interview xD An XOR linked list is a more memory efficient doubly linked list. Instead of each node holding next and prev fields, it ...
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5 votes
4 answers
4k views

Expense-sharing calculation

Friends A, B, C, D go for a trip. They spend on various expenses. Cost of the expense is shared. Example : A spends 100 for breakfast for A, B, C and D D spends 500 for cab for B and C B spends 300 ...
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24 votes
3 answers
8k views

Java Inventory System

I'm often applying to jobs just to test out my skills. I have recently applied to one, had to submit a Java problem, but got rejected. Could someone please review my application briefly and tell me ...
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  • 351
13 votes
1 answer
1k views

Interview coding challenge for iOS Part 2 - the application in Objective-C and Swift

I recently interviewed with a company that needed a C/C++ programmer to work on the iOS side of the products. The job description indicated they needed someone with 4 years of Objective-C and iOS ...
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  • 18.3k
12 votes
1 answer
943 views

Find the peak stock price for each company from CSV data

During the hiring process, a company gave me this test: Q) Consider Share prices for a N number of companies given for each month since year 1990 in a CSV file. Format of the file is as below with ...
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  • 223
12 votes
7 answers
30k views

Given an array of integers, return all pairs that add up to 100

I was recently given this programming challenge on an interview, and I decided to use javascript to solve it. I did, but I'm not happy with my implementation. I can't help thinking there must be a ...
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11 votes
4 answers
808 views

Product of all but one number in a sequence

I was given the following prompt in a coding interview: Given an array of integers, return a new array such that each element at index i of the new array is the product of all the numbers in the ...
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10 votes
2 answers
261 views

Python implementation of find_all_indexes

I got asked this question before in an interview. For example, find_all_indexes('ababc', 'abc') returns 2. This Python function ...
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  • 2,469
9 votes
5 answers
1k views

Find first non-repetitive char in a string

I just had an interview for the C#.NET developer position and I was asked to find the first non repetitive char in a given string without using any library functions but just the basic constructs of ...
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8 votes
3 answers
8k views

Approximate String Matching Interview Question

I was working on the challenge Save Humanity from Interviewstreet for a while then gave up, solved a few other challenges, and have come back to it again. The code below generates the correct ...
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  • 123
7 votes
2 answers
1k views

Reversing a domain name string in Java

Given a dot separated domain name, reverse the domain elements. Example: ...
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5 votes
2 answers
2k views

Project Euler problem 79: deducing a passcode

For one place that I interviewed at (for a Python developer position) I worked with one of the devs on two Project Euler problems, one being problem 79. We talked through different approaches and came ...
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