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

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15
votes
2answers
511 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 ...
25
votes
5answers
2k 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): ...
3
votes
1answer
34 views

Acquiring indices for anagrams of an input string

I am working on an interview question from Amazon Software: Design an algorithm to take a list of strings as well as a single input string, and return the indices of the list which are anagrams of ...
6
votes
2answers
191 views

Finding pairs of numbers within A that add up to N

I am working on an interview question from Amazon Software Interview: Given an integer N and an array of unsorted integers A find all pairs of numbers within A which add up to N I have a working ...
-1
votes
0answers
10 views

Print elements of largest contiguous subarray [closed]

I am trying to implement Kandane's algorithm with an additional property of displaying the elements as well. But this seems to fail for certain input values. I tried to find out but can't see the ...
3
votes
1answer
51 views

Letter Combinations of a Phone Number

I was asked to code a solution in Python in 15 mins. Print all possible word combinations for a given phone number. Numbers 0 and 1 will not be part of the phone number, the numbers can be repeated, ...
4
votes
2answers
387 views

Non-recursive method for finding a ^ n

I am working on an interview question from Amazon Software. The particular question I am working on is "to write a program to find an." Here is my recursive solution to this problem (in Java): ...
3
votes
1answer
71 views

Find the smallest number of square numbers to create n

An interview question I got - Given int n, find the smallest number of square numbers that fit inside n. Example: ...
3
votes
2answers
73 views

Removing duplicates from an array

I recently wrote this JavaScript algorithm for removing duplicates from an array as part of a job interview process, but was turned down for the position after submitting the code. I didn't receive ...
3
votes
2answers
82 views

Immutable Queue in Java using an Immutable Stack

I am new to this Immutability concept and I have some coding experience in JAVA. Recently as a part of internship program, they gave me a 5-day task, which was to implement Immutable Queue. After some ...
3
votes
3answers
198 views

Determining if a pair exists in a large sorted array

I'm doing practice interview questions from here. Here is the one I am currently on - if you are given a very large sorted int array, then check of there exists a ...
1
vote
1answer
70 views

Count the accumulated rainfall in a 2D mountain range

Challenge: Count how much rain will be collected in the valleys between the peaks of a mountain range in a 2D world. The mountain range is defined by a single array of positive ...
2
votes
2answers
103 views

Counting a cycle

An interview question I got - Each element of an int array points to the another element, eventually creating a cycle. Starting at ...
8
votes
3answers
177 views

Computing the relative magnitude of the values in one double array to another

An interview question I received: You are given two unsorted lists of positive doubles x contains the results from experiment 1 ...
33
votes
12answers
3k views

Efficiently squaring each element in a sorted array, keeping it sorted

The other day I was asked the following question during an interview: Given a sorted array, how would you square each element of this array, while keeping it sorted? I froze up and wrote a ...
5
votes
2answers
135 views

Find if a word with wildcard exists in dictionary [closed]

This is a question from a phone interview I had. The question was in 2 parts: a. find("cat") -> T/F suggest a data structure to find is if a word exists in a large dictionary, how will one node ...
3
votes
2answers
242 views

Elevator program code challenge

I recently applied for a job where the company gave me the following prompt for a code challenge. They have since told me "yeah, no thanks" but provided me with no feedback about why they came to that ...
2
votes
1answer
102 views

Deep copy linked list with arbitrary nodes

The original question can be found here. I implemented method 2: Please comment about style, unit testing, code complexity, time and memory space and complexity. ...
7
votes
7answers
996 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 ...
2
votes
1answer
60 views

3Sum 2 Different implementations complexity

These are 2 implementations for the http://en.wikipedia.org/wiki/3SUM problem, The first one is mine. and in the second one I implemented Wiki's pseudo code. Can someone please tell me if there is a ...
6
votes
2answers
111 views

Tree traversal into List

The interview question was to traverse a tree into a list. ...
5
votes
1answer
73 views

Word break problem with dynamic programming

This is the original question. I have implemented it in both ways. If I enter the word "icecream", should I output "ice" "cream" and also "icecream", or just "ice" and "cream"? Is this a good ...
4
votes
2answers
117 views

Pairing anagrams in a string list

The task was to check for pairs of anagrams in a string list. I first sorted all the words. and looped over the letters. The interview continues with a follow-up, to do the same with limited memory. ...
4
votes
3answers
200 views

String reverse and pairing reversed words

These are questions from an interview: Reverse a string Find matching anagrams in a word list ...
1
vote
2answers
99 views

Implement StringBuilder

I was asked this in an interview yesterday. I could add whatever methods, members and constructors I wanted but I couldn't change the signature of the provided ...
5
votes
4answers
531 views

Finding overlapping time intervals

You have two lists with meetings scheduling (start time, end time). Meetings in single list don't intersect. Find all intersecting meetings across the two lists. Is my complexity \$O(N M)\$? If I ...
1
vote
1answer
879 views

Graph Creation and BFS + DFS in C#

I was asked to implement a graph and BFS and DFS. Please comment. Is it understandable? Is my algorithm correct? Are there any optimizations? ...
1
vote
1answer
70 views

Binary search using recursion, iteration, shifted array

Interview question some engineer, asked me to write binary search in 2 ways, Also asked me to write binary search on a shifted array (10 20 1 2 3 4). Wrote that and then asked me to find the offset ...
5
votes
3answers
158 views

Square root implementations

The question was: Write a function that calculates the root of a given number. Answer A = I wrote it for integers. just run up to half of the number Answer B+C = are for double, using Newton's ...
6
votes
3answers
470 views

One character diff - string comparison

The question was: Create an algorithm to check if two strings differ by one character. This wasn't my interview, so I tried to understand the question. Options: just compare the chars one by ...
1
vote
1answer
108 views

Largest subarray with sum equal to 0

This is a typical interview question: Given an array that contains both positive and negative elements without 0, find the largest subarray whose sum equals 0. I am not sure if this will satisfy ...
6
votes
1answer
148 views

Task scheduler coding exercise

In an interview about multithreading I was asked to write code to satisfy the requirements below: In the exercise you need to provide implementation of single-threaded TaskScheduler class with the ...
5
votes
4answers
167 views

Stack with a minimum

A practice interview question: How would you design a stack which, in addition to push and pop, also has a function getMin which returns the minimum element? Push, pop and min should all operate ...
0
votes
1answer
70 views

Matrix: Set a row/col to zero

A practice interview question: Write an algorithm such that if an element in an MxN matrix is 0, its entire row and column is set to 0. ...
-1
votes
1answer
112 views

Java interview code [closed]

I was curious to anyone's thoughts, comments, and input as to something I was presented with during a job interview I went to recently. I was provided with some java code and asked to determine what ...
10
votes
4answers
2k views

Counting occurrences of each word in a sentence

I have been doing this test task for C# Developer role at UBS.London recently and have been rejected. No reason stated yet. Was wondering if you can take a look and provide feedback on what I can do ...
12
votes
4answers
984 views

O(N) vs O(N * N) for Word Frequency Algorithm

I am trying to come up with a better solution to the following problem: Statement You are supposed to write a function which takes the contents of a document in string format and also a whole ...
11
votes
2answers
235 views

Min triangle path - bottom-up

I got a bit intrigued with the recent question DP solution to min triangle path and after a certain chat message I decided that I wanted to implement my solution. Given a triangle, find the ...
6
votes
5answers
220 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 ...
6
votes
5answers
1k views

Given a String, return a boolean if it is a number

Yesterday in an online interview, the interviewer asked me this question: If I give you a string, you have to return if a string is number or not. You are not allowed to use any parse function ...
3
votes
3answers
411 views

pyramid numbers in alternative reverse order

I was asked to write code for the below structure: 1 3 2 4 5 6 10 9 8 7 11 12 13 14 15 And I tried the below code, which works, yet I'm wondering ...
3
votes
1answer
252 views

Finding the longest unique sub-string in a string

I recently interviewed with a company for software engineering position. I was asked the question of finding the longest unique sub-string in a string. My algorithms was as follows: Start from the ...
8
votes
3answers
1k views

Basic string compression counting repeated characters

My task was to implement a method which performs basic string compression by counting sequences of repeating characters. Given "aaabbbccc" it should return ...
2
votes
1answer
262 views

How should I write function to print a singly linked list in a reverse order?

I am preparing for interview and I want to write the function in the way that the interviewers will expect me to write. This is my solution: ...
5
votes
2answers
1k views

Remove Nth Node from End of Linked List

I am solving the well known problem Remove Nth Node From End of List: Given a linked list, remove the n-th node from the end of list and return its head. Assume that n is between 0 and the ...
2
votes
1answer
181 views

Encoding and decoding exercise

I was issued the following coding challenge from a company to write an encoding and decoding function: Encoding: This function needs to accept a signed integer in the 14-bit range [-8192..+8191] ...
7
votes
2answers
169 views

Espresso Queue simulation

I was asked to do a technical test with the following specification, but my solution was rejected and I was not selected for the available position (Junior to "normal" level, with 4 days of time to ...
1
vote
2answers
59 views

Number of maximal PAIRS-values

I had an interview question like this: In a company there are different people. One can measure how well they suits for pair coding as follows: First, let us compute the PAIRS-value which ...
3
votes
1answer
165 views

Interview task to efficiently find compact representation of nodes in tree and find big O time

I recently had an interview problem where I was asked to find a compact representation of nodes in a tree. As an example, consider the following tree: ...
1
vote
1answer
695 views

Print all permutations of a given string in Java

I want to print all permutations of a given string in Java. To do this I create one auxiliary array boolean used[] to check if I have used some character or not. ...