Why Good Programmers FAIL Coding Interviews

Key Takeaways

have you learned data structures algorithms yes practice lead code yes sir why do you fail coding interviews I don't know why can't you get a job that's me four years ago when I was getting rejected in every job interview I took for the last one year before that I had dedicated every single evening of my life trying to learn programming and preparing for the coding interviews even after working so hard it seemed like I was stuck in time and my life was going nowhere no matter how much I prepared and how well I thought the interview went the answer was always same we have decided not to move forward at this time it took me more than 100 interviews before I got my first big job at Amazon and another two years before I got into Google though my confidence was completely shattered by getting rejected again and again in hindsight there were two major benefits of going through this tough experience one I got to travel all around the US in those days companies used to fly you in for on-site interviews and I got to visit SF New York Seattle and many other cities for free too I learned all the ways you can fail a coding interview today I will tell you why so many people fail coding interviews towards the end of the video I'll also tell you how you can use your interviewer to help you solve the coding problem the first reason why people feel coding interviews is because they don't practice like they're giving an extra and explain what I mean by that most people will go to a platform like lead code pick a question randomly and start solving it what they don't know is that problems asked in the actual interviews follow this very famous probability distribution for those who are seeing it for the first time this distribution is called normal distribution or bell curve or this distribution tells us is that most interview problems lie somewhere in the medium difficulty range and getting a very easy or very hard problem is relatively rare just to be clear I'm seeing all this from my own experience and I have not done any math for this anyway I've met so many people who spent their entire time solving easy problems just to boost their confidence and then there are others who spend all their time worrying about the hard problems on lead code in reality it's more beneficial to solve as many medium problems as possible if you look at the distribution of problems I have solved on lead code I have done roughly the same number of easy and hard problems easy and hard problems combined make 37 percent of the total problems I have solved rest of the 63 percent are all medium problems now it's true that you cannot directly start solving medium problems that's why I recommended starting with easy problems and slowly building toward medium problems in my last video talking about practice sessions being very different from the actual interview many people use test cases to cheat during the practice let me show you how many people write the first thing that comes to their head and then hits the submit button and then the use of failing test case to debug their code they fix their solution for this test case and submit again fail again and submit again and this keeps going you might be able to eventually submit your Solution by doing this but remember there will be no multiple Summits during the interview don't get me wrong you can always write your own test cases in the interview debug the issues if there are any but most people would not have any time left to do that so submit failure in the practice might be equal to a rejection in the actual interview I know that I am being too harsh here but the point I'm trying to make is that you should treat your submitted solution as your final solution in the interview once you start saying it that way you will be more diligent and might develop the skill of picking up those small Errors By Yourself rather than by submission talking about submitting your solution many people give themselves hour to solve problems in practice as you might already know an interview lasts somewhere between 45 minutes to an hour in that input introductions in the beginning some time for your questions at the end so giving yourself unlimited time during practice doesn't really prepare you well for the interviews as I mentioned in my last video it's okay to take more time in the beginning but once you become comfortable with interview style questions take a stopwatch start time boxing your practice sessions give yourself 45 minutes to solve medium problems at first and try to get to 30 minutes if you can so far we have discussed all the things that you can do before the interview now we'll move on to the things that you can do during the interview to help you not to fail this is where we will use the interview to help us solve the problem but before that this video is not sponsored so if you want to support us subscribe to the channel when it comes to the actual interviews the first mistake people make is that they don't give themselves enough time to read the problem they get so distracted by the ticking of the time clock that they miss some important details you might think that it can't happen to you but trust me one small detail can cost you really big in the interview let's take this very popular question on lead code as an example in the twosome problem we are given an array of numbers and a target number you need to find two numbers in the array that sum up to this target number you can assume that all the numbers in the array are unique and the solution exists you can pause the video if you want to solve the problem yourself the optimal solution of this problem uses a hash map and this solution has order end time complexity and takes order in extra space now let me change the question a little bit instead of giving you just an array I give you a sorted array and the rest of the problem Remains the Same what will be the worst time in space complexity now the optimal solution of this problem is pointers and doesn't need a hash map so the worst case time complexity Remains the Same but the solution uses no extra space now you would think that you will never miss an important detail like the given array is sorted but when you have already seen the more popular non-sorted version of this problem in your practice time and the interviewer asks you the sorted version your brain can easily skip the sorted part to reach to the solution faster it has happened to me many times and it can happen to you too another reason why people fail coding interviews is because they violate the basic design principles of programming in the interview this is how most people's interview solution looks like everything that comes in the mind just gets stumped in this one place and that is the final solution in reality if you want to make your life easier you should break your solution into the helper functions if possible this is especially important if you are using the same code again and again there are three major advantages of doing this one you don't look like a newbie who doesn't really know how to write code at an actual job too if the interior wants you to run the code and you need to debug the solution having well-defined helper functions makes it very easy to debug that's because you can test is your helper function separately if needed lastly when you don't have enough time to go to the full solution you can just tell the interviewer that you will write this helper function that has this particular Behavior at the end if you have some time left in the end you can obviously write this helper function but if you don't the interval might be able to see that writing the helper function is actually easier than the actual code you wrote during the interview that way there will be more willing to let it go if you complete rest of the solution this only works if the helper function is not really the core part of the solution so make your life easier by using helper functions another reason why people fail coding interviews is because they don't really use their interviewer enough most people think that the interviewer is just there to judge you and there is some sort of adversarial relationship between them and the interviewer in reality your interviewer is just another person who like most people wants to have a good conversation they are there to unblock you if you get stuck so you have to use them wisely first way you can use your interviewer is by clearly explaining Your solution to them that's because most humans cannot resist the Earth to correct you if you're saying something wrong and if they correct you listen to them carefully because they'll drop some very useful hints by doing this you can avoid the situation where you end up quoting the wrong algorithm and it's already too late to correct your mistake second way you can use your interviewer is by paying attention to the clarifying questions they ask you when you're coding Your solution most of the time interviewers do this when they have spotted something wrong in your code so always pay attention to your interviewer and this leaves us with the most common reason why people fail and that is they focus too much on the things that are outside their circle of control let me explain this is your circle of concern it contains all the things that you can care about for your interview these things include whether your interviewer is a junior or a senior engineer whether the name of your college or having noted we will automatically get you rejected or if your interviewer will show up on time or not all these things impact the outcome of your interview and within this circle of concern is a smaller Circle that is your circle of control this circle contains things like whether you have good foundational knowledge of data structures and algorithms whether you practice enough questions on lead code or whether you will show up on time for the interview these are all the things that you can control so stay inside your circle of control and keep improving yourself once you start doing that nobody will be able to stop you all the tips that I gave you today are useless if you don't practice enough problems for your coding interviews and Lead code is the best resource to do that if you want to know which exact questions to practice on lead code and how to practice them watch this video my name is sahil and I'll see you in the next one