Live Mock DSA | GeeksforGeeks

Key Takeaways

foreign [Music] foreign interview session and uh with me we have gargi giri today so uh let me give you a quick introduction about the session and then we can start so my name is gaurav Kumar shop and I am associate Mentor at Geeks for gigs and in this session I will be interviewing a candidate named guardi giri okay yeah just a minute are you here foreign foreign into uh can you kindly uh share your screen with the doc file that I have already given to you just take your time no worries [Music] hello yeah uh yeah to uh do I need to give an intro [Music] uh yes yes uh can you kindly First share the screen uh you will have a presentation okay okay yeah yes and can you go to the doc file yeah yes very well so uh let me uh yeah yeah sure just give me a minute so hello everyone let me one second begin and I apologize for the inconvenience cost so uh today's 25th November and this is a mock interview session and so basically I will be interviewing a student named and how is the session going to proceed is that we will be having a proper formal round of uh as an as an interview which basically happens uh during the selection process of various companies okay and meanwhile I would also like to say that today since it's Friday Black Friday sale is going on in Geeks for geeks website so basically what you can do you can if you are buying courses today you will get a flat 25 discount on all of the courses so kindly check that out there are amazing courses on the platform so let's begin with the interview so hello kargi how are you yeah I'm fine okay uh tell uh give a little bit introduction about yourself uh I'm a second year student of Heritage Institute of Technology uh be taken electronics and communication engineering with a passion for core as well as the code part so I'm there uh and my skills include C and CPP based okay very well can you say something apart from your CD anything anything interesting about yourself any hobbies [Music] uh yeah I I love to read about space science space science oh that's very interesting are you okay uh I went through your CV and uh it was it was mentioned that you are very comfortable with C plus plus language so uh for today uh actually I'm more comfortable with c and I'm currently learning C plus plus but more comfortable with c uh good at C plus plus Basics means uh the C part of C is a subset of C plus plus basically so I can tell that I know that as well okay okay no worries okay so uh let's begin with the uh questions so I have already shared a document file with you I will put the first question there okay thank you [Music] yeah so can you see the question so let me just explain your the question to you so uh you have been given an array and the array contains both positive as well as negative numbers now your task is to compute the length of the largest sub array with some zero so uh basically in the example you can see that if the input is 8 there are eight numbers but uh you will see that the largest sub Arabic sum equal to 0 is from minus 2 to 7 that is minus 2 2 minus 8 1 and 7. as you can see that uh that at the sum is equal to zero so you have to return its length is the question clear um wait one second yeah yeah take your time no worries can you explain it once oh yes oh no worries no worries so basically uh I have already given you an array so the array contains both positive and negative numbers and your task is to compute the length of the longest sub array such that the sum is equal to zero in that sub array so as you can see I have already selected a summary that starts from -2 and ends with seven so that is a sub array and when you see when you compute the sum of all the numbers that is minus 2 plus 2 minus 8 plus 1 plus 7 you see the sum is equal to 0 and the length of that sub array is 5 so you have to return five okay you can see there are very small sub arrays also such that the length is equal to zero but such as the sum is equal to zero but the length are not the maximum so we you will not output that it will output that particular sub array in which the length is maximum the largest sub array okay so how are you going to struggling uh here we have to uh means I have to First Traverse each element uh one by one of the surveyor like a first 15 will will be traversed and minus 2 10 plus 2 minus 87 and so on and for each element if the element is less than zero then uh I will put a count variable means uh I will put two variables here or I can use one variable as a bit is for a for an element which is lesser than 0 like negative integers minus 2 and minus 8 here I will use a variable named count and the count will be increased when a negative integer is uh traversed okay and um for if the element is greater than 0 that is the positive integer then um I will name another count positive variable and that will be incremented for every positive integer variable will help because we are not asking to count anything we are asking you to return the length of the longest sub array such as sum is equal to zero maybe uh you need to check this sum that is when you are traversing try to compute the sum of the sub I that you are traversing and if that's the battery is I think that um I will mean some for I will um arrange all the negative integers in one and the positive inter and then sum it up and if this is you cannot change the array okay the array has been already given to you and the array stays in that order only now uh you see that you have to return the length of the longest sub array sub array is basically a part of the array which is a contiguous in nature a contiguous part of the array such that the elements in that Subaru the sum is equal to zero okay so if you are arranging the arrays the number will get uh the number will get distorted so in that case we are not sure that whether that particular sub array is the original salary or not so we cannot do that are you getting okay okay yes okay let me give you a hint uh what you can do is that do you know that uh I will uh basically ask you to go across all possible sub arrays okay and can you think how can you do it how can you go across all possible salaries uh yeah yes yes like uh like in case of March thought or those things we are divide an array into many sub arrays that approach we can apply here not exactly you cannot do that okay let me give you another small end let's say you are standing on the number 15 okay so uh if the number 15 is also part of a sub array the number 15 and the next number is also part of the sub array and the number 15 the next number and the next number is also a part of sabari okay so you can see when you're standing on the number 15 you can create multiple sub arrays so basically when you are standing on any number you will be able to create multiple sub arrays right so can you devise a logic in which you can Traverse all possible sub arrays and check for the given condition as asked to the question yes [Music] yes take your time if you have any question you can ask me I will be happy to help much [Music] [Music] foreign [Music] uh Gandhi I would request you to kindly uh vocalize whatever you are thinking so that if you are thinking in a wrong approach I will just guide you there actually I was first trying to create that um a program which will uh calculate the length of the array um with uh in Array and in N is n is the size of the array uh where um where I means of I will encounter yeah I will Traverse each note and try to sum it up uh like [Music] like the first element will be um the base of that and then uh means I will sum it up with the write the next element yes you are going correct go ahead like for I will create I will start a for Loop uh which will go till the size of the array and I will um create a variable named maybe say some maybe yeah maybe called some some variable which will be incremented after each traversal traversal of each element okay which will be incremented and uh summed up as well with the previous element uh and if [Music] and I can share means and check if um this summer is going to be zero or not it means there I can check ah yes you have to check that because the question is asking that only then what will you do [Music] but here I am getting the problem like I am checking from the first element uh but for this question the output is um the sub array containing the middle elements so how to avoid the first element means the first element is skip this part is creating a confusion that is what that is what the question is asking basically so let's say if you start creating the Subarus from the first element so you take one Loop and create all the summaries then again you use a nested Loop to create other server starting from the second element then the third element okay so this is what I was trying to get from yes but if if they are submarical for any like for any other example if this is the longest Subway will contain the first element as well then I will I mean I'm skipping the first one what is the condition for that and here I'm getting the problem so you cannot skip a first element basically what I told you is that you have to uh you have to go through all of all possible salaries that are possible okay [Music] and then check whether the sum is okay that is what I was trying to say so so I I almost told you the entire concept so can you write a small implementation of pseudocode or anything of this approach uh yes this is for the maximum length I'm writing the code code for the maximum length foreign [Music] thank you [Music] [Music] foreign [Music] thank you [Music] [Music] [Applause] [Music] foreign [Music] [Music] [Music] [Applause] thank you [Music] [Music] [Music] um explain me while you are writing so that uh actually I'm getting problem after this part means they are up to this part I have I had explained earlier and after this so you are trying to you're trying to get the sum of the numbers and you are trying to check that whether that sum is equal to equal to what is first this variable first what does this indicate actually I was thinking that um if the number is um zero then what should you do what is the question asking thing the question is asking that if the sum is equal to 0 in that case you have to find the maximum length across all possible so so what operation can you do that will help you store the maximum length [Music] uh people I'm traversing each element from the first one and I'm initializing the um array with the first element which pre underscore sum plus equals erri for the first element the sum will be the first element itself and then for the next one it will be added up with the next element and if the sum of those elements is equals to 0 then I I'm going to calculate the size means that size but again here that problem is encountering that [Music] uh uh Garvey tell me why exactly are you doing Max size plus plus I don't think that it is serving any purpose yes uh actually I I want to print the size of the maximum size there I should increment it before anywhere okay uh let's see uh so uh can you tell me what is the first uh the whatever surprise I can even increment it's means Max size is equals to n if um this please uh pre underscore some equals to equals to zero then this Max size uh must be that element uh in which it is currently working okay uh so I can use a a temporary key variable count equals to 0 and which will be incremented and if and if this is but this can be a pseudo code for me oh the only elect here is um that they it is not creating sub areas it is checking for the uh some of the array equals to zero or not means at which point from the first element it is not going away from the first element huh yes exactly uh so basically your program is using one Loop and with that Loop it is trying to get the always serious message that the starting point of the server is the first element okay yes please the starting is fixed getting fixed and the end is a variable here but I want to make this chart also variable so how can you do that your code is partially correct but uh what this food will basically run if the if it happens at the longest salary uh such the starting point is also the first element but we don't want that we wanted the starting point can be any element so can you try to modify this concept a little bit so that uh you are traversing across all possible sub arrays yeah I have to create a variable for the first element as well hello see uh you're in your Loop the variable I the variable I was basically uh traversing across the loop right so and after that the variable prism was taking the sum from the I equal to 0 to uh whatever I you are traversing so can you do the same concept but uh this time the first element will also be variable that at the first time you are doing uh considering the first element then the second then the third so how can you implement this concept in the form of a code um [Music] foreign that is a song what can you help me just a bit for making yourself a variable uh you are trying to uh write a tested Loop that is correct okay but uh see if you try to write from J equal to n then you have to think accordingly okay see um okay what can I say here is that let's say the outside Loop basically controls the uh the starting point okay and the inside loop will control all possible server is starting from the starting point that the ith Loop is controlling so I will recommend you to write the code in that fashion ah can you repeat the last line please what I'm saying is that what you can do you can use the outside Loop the eye Loop to control the first element of the sub array and the inside loop to control uh to Traverse the sub array starting from the first element what the is Loop is controlling okay so okay now uh the uh this is controlled by the GH element and the eye look should control the first one right [Music] [Music] thank you [Music] [Music] [Applause] okay we are kind of running short on time so uh can you tell me uh what exactly can be the time complexity of your approach that you were writing uh Big O of n Square and Y is uh because it means in the worst case this will be bigger of n Square as two of our Loops are working here one under another so for the first for Loop um the time complexity will be n and for the other one as well it will be n so n into n that will be n Square means for each pass of the ith one and N J passes are occurring so Square and what is the space complexity of your code space complexity [Music] that I cannot tell perfectly means uh just to think uh like are you using any extra space in your problem not exactly not using an extra space okay uh okay uh so uh I am putting the link of this question in the chat box but uh since we have uh we are running short on and we'll move to the next question but uh you can practice that question after the interview session is over okay okay and thank you foreign so let's move to the next question then so the next question I am putting it in the chat box yeah so uh can you see the next question so the question says that you have been given a single linked list of nodes now your task is to find the middle element of the linked list for example if the linked list is starting from 1 10 2 then 3 then 4 and then five so the middle node will be 3 so you have to Output 3 but in case let's say if there are even number of nodes so there will be two middle nodes so in that case we'll print the second second element for example if the link list starts from 1 then 2 then 3 then 4 then 5 and then six then the middle node will be three and four both but according to the condition you have to print four the second element if your case is uh if it's a even length so how will you solve this so let's proceed with this question let me give you a some example problem also a sample input output [Music] yeah so uh meanwhile Garg is thinking so there are 70 the people with me right now watching this interview session so in case if you want to have your own interview uh on the Geeks for geeks YouTube channel you can fill the form in the description and uh you will be called and you will be assigned a mentor and we will have a live session of the interview okay so uh in case if anyone is in their second year or in their third year uh who are preparing for internships and placements yeah this can be extremely good opportunity because uh practicing more of interviews will definitely help you a lot thank you now yes here we can um we can in this case also we can Traverse each element and count the number total number of nodes that is n here n is the total number of nodes and again we can run the same language for n by two number of nodes or this n by 2 will be valid for um n by 2 yes n by 2 will be the middle element in case of odd number of elements n plus 1 by 2 will work when uh the N is even then um n by 2 will be the middle element and for odd number or odd value of n n plus 1 by 2 will be the um middle element yeah okay uh you are correct can you write a pseudo code explaining your approach uh just assume that uh you have been given the head of head pointer of the linked list and now you have to write a code that will basically Implement whatever you have said be EP s [Music] [Music] foreign foreign [Music] me me [Music] guys in order to write the struct part of the linked list just the logic so can you explain to me that uh whenever you are writing the code just estimate to know what you're doing better actually I have written this for the means uh Forum this is for them Ling list with n number of nodes means um this is the English traversal code this will work for any number of nodes and then if this is just for the printing part of that link list and this um with this truck node I've created a the data part of each language and the link part next of the English which will Point towards its address that that is to the next node okay so uh basically how can you calculate the length of the linked list why are you printing it yes I will create a variable here now the number of nodes are counted by the account variable here okay uh now I can get oops without variable will be printed by this count function printer function so we are I get the um I got the total number of nodes here now I will print uh I will calculate the middle element it means I can write it in mid equals to zero net is equals to [Music] foreign [Music] foreign foreign [Music] middle function which will basically print in the beginning please thank you foreign [Music] [Music] foreign me me hello [Music] oh yes can you so yes you first calculated the length of the linked list by doing a traversing and then you again for August but this time it was length or divided by two so okay I am again printing the middle element where I am creating the first node as star hat then um again I guess due to network issue the candidate has left the stream let's wait for her to join uh meanwhile I would like to like everyone present in the live stream to kindly check out the Geeks for geeks website where we are having Black Friday sale and you can get uh 25 off on all the courses available there and I guess there are pretty much pretty amazing courses for your preparation of your interview and other stuffs and uh meanwhile if you are if you would like to have your own interview session with the mentors at weeks for weeks you can fill the form in the description of the stream and upload your CV there and very soon a member of our team will connect with you and we can have a live session this can be extremely a great opportunity for all the people who are preparing for their upcoming internships and placements foreign foreign if she is unable to join I can just give the feedback and we can conclude this session okay so let us move to the feedback part of the session so uh I guess she is unable to join but this will be recorded and she can get get to listen to her feedback so uh basically uh let me first tell about the preparation level so uh as far as uh what I can judge is that the preparation level of the candidate is not up to the mark and she needs to prepare well okay uh we have kalki here she has joined the Stream yeah hello um uh Guardian since uh we are running a bit short on time so let's keep that uh on our pause so uh basically uh the concept that you were writing was correct and about how to find the middle element of the linked list okay so uh let's move to the feedback part since you are in your second year of your study uh so basically what can I make out of the session is that uh your preparation level is not exactly up to the mark that is required for uh internships and places right so uh so what I will what I want you to basically do is focus on learning the concepts learning the language as well since uh you are comfortable with C right now but I would request you to learn C plus plus as well because C plus plus is an extremely powerful language considering data structures and algorithms okay so uh so basically um yeah so let me continue with the feedback yeah apart from that uh yeah so another important factor considering interviews are the communication skills so whenever you are giving an interview so try to communicate your thoughts with the interviewer okay so whenever an interview throws the question try to make sure that you are you have properly understood the question in case if there is there is any missing information try to get it clarified with the elderflow let's say if there are certain edge cases you are not able to understand try to get it sorted with the interview just in the beginning after that try to explain whatever comes to your mind it doesn't have to be the most optimal solution okay it can be a very simple very Brute Force solution so this will help you get started with the flow of solving the problem and after you say The Brute Force solution the interviewer will ask you to optimize the solution and after he says that so then start optimizing the solution in a much better way if you are telling your n Square approach then tell a linear approach or an N login approach and while you're explaining it make sure to list down all the data structures and all the algorithms that you are using to solve that question okay and up after that after you explain your approach never forget to mention the time complexity and the space complexity of your approach both okay and if there are certain interesting facts or interesting observation in that question do make sure to bring it up to the interview okay so this is the most important and I think everyone uh lacks this delivery card while dealing with interviews so make sure this is a lot this is to improve upon the skin apart from that it may happen that you are stuck in your interviews in the question you are not able to get the question so it's completely okay to ask the interviewer that uh tell about certain hints that may help you to reach the solution faster okay so basically this is actually a very positive sign during interviews because uh interviewer chances are connected based on two factors like whether the person knows the concept and if the person doesn't know the concept how quickly the person can reach to the concept by taking hints okay so if if you do not know the question then if you do not know the answer then that's okay but if you can reach to the answer after knowing of any hint after taking the hints then that is a very good quality uh interviewer looks in a candidate so make sure to ask as many uh hints as possible and try to understand try to analyze that hint and reach the solution okay so this is the second part third part uh as I've already mentioned all this uh tell the brute for solution first and then optimize further and listing down the time and space complexities at every approach okay so this is done now finally after the question gets over uh the inter always ask the interview that are you satisfied with my solution so is there any way of improvement can I optimize it any further so the interviewer may have any ideas of his own he may share with you so this will increase the interaction between the interviewee and the interview which is very important because you know that during an interview the candidate may get nervous but having a proper interaction with the interviewer will help you to ease out that discomfort and nervousness and this will basically prove to be quite productive okay so uh this is the feedback from my side and I hope uh gargi will listen to the recording will get to know this and uh meanwhile uh all the 34 people who are uh joined has likes uh this live session kindly subscribe to our Channel and like it as well and uh if you want your interview to get a scheduled with the mentors at Geeks for geeks we can just fill the form and uh after you fill the phone we will contact you and get your interview scheduled okay you can put your CVS as well this is a very uh because since you are preparing for your internships taking mock interview will basically let you know the where you are lacking as a candidate okay because there are certain things which you cannot prepare by yourself the the interview part we have to have to take help of others you have to do a lot of mock interviews then only you will get to that level okay yeah and uh one more thing Black Friday sale is also live and uh there are there are very I mean very amazing courses on the GFC platform you can get all of the courses at a flat 25 discount just for today okay I hope everyone can check that out so uh we are almost to the end and uh so let's conclude the session and thank you everyone for uh joy in this session and enjoy have a great weekend ahead