Cracking the coding interview

510 Pages·2013·50.05 MB·English

CRACKING THE
CODING
INTERVIEW
150 Programming Questions and Solutions
Gayle Laakmann McDowell
Founder / CEO, CareerCup.com
CRACKING THE
CODING
INTERVIEW
5th Edition
ALSO BY GAYLE LAAKMANN MCDOWELL
THE GOOGLE RESUME
How TO PREPARE FOR A CAREER AND LAND A JOB AT
APPLE, MICROSOFT, GOOGLE, OR ANY TOP TECH COMPANY
CRACKING THE
C O D I NG
I N T E R V I EW
5th Edition
150 Programming
Questions and Solutions
GAYLE LAAKMANN MCDOWELL
Founder and CEO, CareerCup.com
CareerCup, LLC
Palo Alto, CA
CRACKING THE CODING INTERVIEW, FIFTH EDITION
Copyright © 2008 - 2013 by Gayle Laakmann McDowell.
All rights reserved. No part of this book may be reproduced in any form by any
electronic or mechanical means, including information storage and retrieval systems,
without permission in writing from the author or publisher, except by a reviewer who
may quote brief passages in a review.
Published by CareerCup, LLC, Palo Alto, CA. Version 5.01390210100131.
No part of this book may be used or reproduced in any manner without written per-
mission except in the case of brief quotations in critical articles or reviews.
For more information, contact [e-mail].
978-0984782802 (ISBN 13)
To Pauline "Oma" Venti
for her eternal support
Table of Contents
Foreword 1
Introduction 2
I. The Interview Process 5
Overview 6
How Questions are Selected 7
Timeline and Preparation Map 8
The Evaluation Process 10
Incorrect Answers 11
Dress Code 12
Top 10 Mistakes 13
Frequently Asked Questions 15
II. Behind the Scenes 17
The Microsoft Interview 19
The Amazon Interview 20
The Google Interview 21
The Apple Interview 22
The Facebook Interview 23
The Yahoo! Interview 24
III. Special Situations 25
Experienced Candidates 26
Testers and SDETs 27
Program and Product Managers 28
Dev Leads and Managers 30
Start-Ups 31
IV. Before the Interview 33
Getting the Right Experience 34
Building a Network 35
Writing a Great Resume 37
V. Behavioral Questions 39
Behavioral Preparation 40
Handling Behavioral Questions 43
VI. Technical Questions 45
VI Cracking the Coding Interview
Table of Contents
Technical Preparation 46
Handling Technical Questions 49
Five Algorithm Approaches 52
What Good Coding Looks Like 56
VII. The Offer and Beyond 61
Handling Offers and Rejection 62
Evaluating the Offer 63
Negotiation 65
On the Job 66
VIII. Interview Questions 67
Data Structures 69
Chapter 1 | Arrays and Strings 71
Chapter 2 | Linked Lists 75
Chapter 3 | Stacks and Queues 79
Chapter 41 Trees and Graphs 83
Concepts and Algorithms 87
Chapter 5 | Bit Manipulation 89
Chapter 6 | Brain Teasers 93
Chapter 7 | Mathematics and Probability 97
Chapters | Object-Oriented Design 103
Chapter 91 Recursion and Dynamic Programming 107
Chapter 10 | Scalability and Memory Limits Ill
Chapter 11 | Sorting and Searching 117
Chapter 12 | Testing 123
Knowledge Based 131
Chapter 13 | C and C++ 133
Chapter 14 | Java 141
Chapter 15 | Databases 147
Chapter 16 Threads and Locks 153
Additional Review Problems 161
Chapter 17 | Moderate 163
Chapter 18 Hard .167
CrackingTheCodinglnterview.com VII
Table of Contents
IX. Solutions 169
Data Structures 171
Chapter 1 | Arrays and Strings 171
Chapter 2 | Linked Lists 183
Chapter 3 Stacks and Queues 201
Chapter 41 Trees and Graphs 219
Concepts and Algorithms 241
Chapter 5 | Bit Manipulation 241
Chapter 6 | Brain Teasers 257
Chapter? | Mathematics and Probability 263
Chapter 81 Object-Oriented Design 279
Chapter 9 | Recursion and Dynamic Programming 315
Chapter 10 | Scalability and Memory Limits 341
Chapter 11 Sorting and Searching 359
Chapter 12 | Testing 377
Knowledge Based 385
Chapter 13 | C and C++ 385
Chapter 14 | Java 399
Chapter 15 | Databases 407
Chapter 16 | Threads and Locks 415
Additional Review Problems 429
Chapter 17 | Moderate 429
Chapter 18 | Hard 461
X. Acknowledgements 491
XI. Index 492
XII. About the Author . 500
Join us at www.CrackingTheCodinglnterview.com to download full,
compilable Java / Eclipse solutions, discuss problems from this book
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VIII Cracking the Coding Interview
Foreword
Dear Reader,
Let's get the introductions out of the way.
I am not a recruiter. I am a software engineer. And as such, I know what it's like to be
asked to whip up brilliant algorithms on the spot, and then write flawless code on a
whiteboard. I know because I've been asked to do the same thing—in interviews at
Google, Microsoft, Apple, and Amazon, among other companies.
I also know because I've been on the other side of the table, asking candidates to do this.
I've combed through stacks of resumes to find the engineers who I thought might be
able to actually pass these interviews. And I've debated in Google's Hiring Committee
whether or not a candidate did well enough to merit an offer. I understand and have
experienced the full hiring circle.
And you, reader, are probably preparing for an interview, perhaps tomorrow, next week,
or next year. You likely have or are working towards a Computer Science or related
degree. I am not here to re-teach you the basics of what a binary search tree is, or how
to traverse a linked list. You already know such things, and if not, there are plenty of
other resources to learn them.
I am here to help you take your understanding of Computer Science fundamentals to
the next level, to learn how to apply those fundamentals to crack the coding interview.
The 5th edition of Cracking the Coding Interview updates the 4th edition with over 200
pages of additional questions, revised solutions, new chapter introductions, and other
content. Be sure to check out our website, www.careercup.com, to connect with other
candidates and discover new resources.
I'm excited for you and for the skills you are going to develop.Thorough preparation will
give you a wide range of technical and communication skills. It will be well-worth it no
matter where the effort takes you!
I encourage you to read these introductory chapters carefully. They contain important
insight that just might make the difference between a "hire"and a "no hire."
And remember—interviews are hard! In my years of interviewing at Google, I saw
some interviewers ask"easy"questions while others ask harder questions. But you know
what? Getting the easy questions doesn't make it any easier to get the offer. Receiving
an offer is not about solving questions flawlessly (very few candidates do!), but rather, it
is about answering questions better than other candidates. So don't stress out when you
get a tricky question—everyone else probably thought it was hard too.
Study hard, practice, and good luck!
Gayle L. McDowell
Founder / CEO, CareerCup.com
Author of The Google Resume and Cracking the Coding Interview
CrackingTheCodinglnterview.com