Paytm Interview Experience | Set 25
I was interviewed by Paytm for a Software Engineer profile.
Round 1: “Coding Round”
The coding test was taken on Mettl. Two questions, 1 Hr time.
- An adhoc problem. Given an array of marks for ‘n’ questions. Find the minimum total marks. Constraint: two questions cannot have same mark.
- A DP problem. The question was put into a story. It was on Longest Palindromic Substring. https://www.w3wiki.net/longest-palindrome-substring-set-1/
Each question had around 10-12 test cases to be passed. A list of candidates was announced for F2F interview.
It was going to be a long day! Phew!
Round 2: F2F (1 Hr)
Basic Introduction. The interviewer went through the Resume, asking question on it.
Was asked to implement Immutable class. A detailed discussion on Immutable classes.
Was Asked to implement and explain inner working of Thread Pool and Semaphores.
- https://www.w3wiki.net/create-immutable-class-java/
- https://www.javacodeBeginner.com/2016/12/implement-thread-pool-java.html
Round 3: F2F (1 Hr)
Basic Introduction. The interviewer went through the Resume, asking question on it.
A detailed discussion on HashMap and inner working of it. Discussion on how/when to increase size of it. Discussion on threshold value and load Factor.
http://javaconceptoftheday.com/initial-capacity-and-load-factor-of-hashmap-in-java/
Was asked to write production code for implementing a LinkedHashMap where items when retrieved comes out in the same order as inserted. An update on already present element makes it as a new element.
Production level code for three functions were asked to implement with every case covered:
- add()
- delete()
- printAll()
Asked me about its Time/Space Complexity.
Round 4: F2F (~35 Mins)
Basic Introduction. The interviewer went through the Resume, asking question on projects I’d on it in detail.
Was asked to explain working of a Trie, as I had used it in one of my projects. Also few Question related to OS (I don’t really remember them now!)
Round 5: F2F (HR Round)
Basic HR questions. It went on a fun track asking about travel and places to visit around:p
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