passing a coding interviewProfessional Programmer CV We walked out of the hiring meeting frustrated, again. Of the ten "passable" candidates wereviewed that day, none would receive offers. Were we being too harsh, we wondered?I, in particular, was disappointed. We had rejected one of my candidates. A former student.One who I had referred. He had a 3.73 GPA from the University of Washington, one of thebest computer science schools in the world, and had done extensive work on open sourceprojects. He was energetic. He was creative. He worked hard. He was sharp. He was a truegeek, in all the best ways.But, I had to agree with the rest of the committee: the data wasn't there. Even if my emphaticrecommendation would sway them to reconsider, he would surely get rejected in the laterstages of the hiring process. There were just too many red flags.Though the interviewers generally believed that he was quite intelligent, he had struggledto develop good algorithms. Most successful candidates could fly through the first question, which was a twist on a well known problem, but he struggled to develop his algorithm.When he came up with one, he failed to consider solutions that optimized for other scenarios. Finally, when he began coding, he flew through the code with an initial solution, but itwas riddled with mistakes that he then failed to catch. Though he wasn't the worst candidatewe'd seen by any measure, he was far from meeting "the bar." Rejected.When he asked for feedback over the phone a couple of weeks later, I struggled with what totell him. Be smarter? No, I knew he was brilliant. Be a better coder? No, his skills were on-parwith some of the best I'd seen.Like many motivated candidates, he had prepared extensively. He had read K&R's classic Cbook and he'd reviewed CLRS' famous algorithms textbook. He could describe in detail themyriad of ways of balancing a tree, and he could do things in C that no sane programmershould ever want to do.I had to tell him the unfortunate truth: those books aren't enough. Academic books prepareyou for fancy research, but they're not going to help you much in an interview. Why? I'll giveyou a hint: your interviewers haven't seen Red-Black Trees since they were in school either.To crack the coding interview, you need to prepare with real interview questions. You mustpractice on real problems, and learn their patterns.Cracking the Coding Interview is the result of my first-hand experience interviewing at topcompanies. It is the result of hundreds of conversations with candidates. It is the result of thethousands of candidate- and interviewer- contributed questions. And it's the result of seeingso many interview questions from so many firms. Enclosed in this book are 40 of the bestinterview questions, selected from thousands of potential problems.