Answer keys are released for Gate2020

Question

http://gate.iitd.ac.in/qp2020.php

Comments

Is there any difference in the answer provided by gate overflow and Official answer key?

---

@siddharthd Only 1 I think, $O(n^2)$ for insertion in linked list is official answer while GO had $O(n\ lg\ n)$

---

The TLB answer by GO is 725-738 and in official answer key it is given as 154.5-155.5. Is this question worth challenging?

---

What do you think about the aptitude question P, R, T one question. Should this be challenged as I think it was an incomplete question?

---

Hi @Arjun Sir , Can we challenge this question.Since it is nowhere mentioned that sorted order should be maintained after every insertion.We can simply insert all the elements then sort using merge sort which will take o(nlogn). time

---

The TOC Regular Expression question ans is given as D in the answer key. But all options are incorrect as per GO.

---

I think none of the answers can be challenged.

---

Nope.

---

Regular expression one should be challeneged..

---

yes exactly

---

Will the GO Rank predictor key be changed? if yes, then when?

---

TLB & Regx Question should be challenged and i think answer will change.

---

Exactly my point, even the word maintained is used. So why can't all elements be inserted in the linked list and then sorted using merge sort. You will definitely call it that after inserting n elements in an empty linked list, it has been maintained in sorted order. ​​​Benefit of doubt must be given to the examinee if what they wanted to imply was that linked list should be kept in sorted order after every insertion. 

---

The language is pretty clear. Maybe you didn't understand it.

(Maintenance can only be done over a course of time.)

---

@johncenaoriginal Agreed. But won't you call a room that is all neat and clean a well maintained room. I can understand what you are trying to say, I myself have changed this answer from n^2 to nlogn while reviewing precisely because an answer which was asymptotically tighter was present. Try re reading the question after reading what I have said without any cognitive bias, you will understand what I am trying to say.

---

yeah, elements need to be maintained in sorted order means you have to just sort, it is not necessary to insert 1 by 1. So you can sort before or after insertion. nlogn should be the answer.

---

What should be the answer of linked list question ?? N^2 or nlogn .

---

it should be nlog n
Please provide resource

---

Is link opened for challenge?

---

@amanjuyal Both can be the answer depending on how you interpret the question. If extra DS can be allowed then look at Vimal Patel's answer under the question, if you have the elements available before hand then look at the offline sorting technique which people are talking about and if you think that the word maintained can have another meaning like I am arguing above and elsewhere on the Internet, you can go for it. These are three major arguments that can work in favour of nlogn. 

---

@srestha The official websites says it will be open from tomorrow till the 21st, the link doesn't seem to be active as of now. What are your thoughts on this n^2 vs nlogn saga though?

---

Final answer keys are out.

---

That mean in TLB question they haven't make any change ?

---

Yes No change .