Company : One payu india ,Gurgaon
Profile : Software Engineer
Round 1 : Coding Round
Consisted of 5 coding questions to be done in 1 hour .Most of them were based on algorithms but some were adhoc also . Everyone has a different set of questions jumbled from a pool of questions . Do 3 and you will definitely be through to the next round.
Around 30 were shortlisted for interviews .
The interviewers focused mainly on coding knowledge and skills .
Can’t remember all of the questions.
In all three interviews I have to make codes for all problems.
Tech interview 1(50 min) :
1. Tell me about urself.
2. Given an array of ints of size n having no. from 1 to n+1 . find the missing no. Atleast two solutions expected .
3. P node problem in linked list .Its solution . I told him Floyd cycle .he asked why I moved fast pointer by two and not by four . told him we have to check multiple conditions to find whether there is a second/third /fourth node otherwise if we try to access a node that doesn’t exists then it’s a runtime error. He looked satisfied.
4. What is a stack ?
5. Find leader elements and ii) next greater element for all in an array.
5. Find whether a tree is a BST or not . Gave him 2 solutions :Inorder traversal and check if sorted with or w/o array , use recursion in top down manner. He was expecting another solution which uses property of bst . Told him the min , max solution .told me to code latter two .
6. Game question : 2 players play alternately . 1st always has to win.he can choose whether to play first or second.there is an array of coins(ints).at a time the player can choose only extreme ends.ex: 1 3 2 17 9 so player can choose only 1 or 9,if it chooses 9 then other can choose only 1 or 17.finally the player with max coins sum will win . what strategy will player 1 choose to win always.. Solved it with some help from interviewer . He extended the ques. Now the player 1 has to win with max sum (a good dp question).
The round went very good and the interviewer said he was impressed 😀 .
Tech Interview 2(1 hr):
1 . Given a text .there is a string in the text somewhere which is rotated version of original string .find and correct the rotated string in the text .ex: text – there was a company named entureacc in 1990s. string : accenture . gave the solution using 2 arrays . he told me to take advantage of space(‘ ‘) and code solution. So i used space as delimiter and coded solution using a 26 size char array.
2 . Reverse every word in a string . Code it . make sure ur code doesn’t have any bugs and try to code faster.
3 . Discussion onQues asked in prev round.
4. Multiple and multilevel inheritance in java. Is there multiple inheritance in java and why ?
5. Design questions : i)Design a car , ii) Design an elevator system .
6. Camel banana Puzzle . Google it for problem statement .
7. Boundary and zigzag Traversal in a tree.
This round went perfectly and I was called for 3rd round immediately .
Tech interview 3(50 min):
Seemed like a police interrogation room with only 2 chairs and a table.The interviewer told me that I have to write complete codes for all probs in this round. I stayed confident…from outside ..
1) Rotate a square matrix by 90 degrees using O(1) space .The question was new to me and after struggling for about 10-15 minutes while the interviewer was busy with his laptop, I solved it and wrote complete code for it.
2)Given a binary tree ,I was given two pointers p1 and p2 to two nodes in the tree I have to swap the subtree rooted with these nodes . he asked me the base cases for this prob. I told him none of p1 and p2 should be ancestor of other .p1 and p2 should be in tree and they should not be null . Another constraint was that I can traverse the tree only once. I told him that I will find lca of both nodes and keep track of all ancestors of both using array and then use this array to perform swap. told me to code it.
HR round (Telephonic):
Just a formality. Asked everything about myself. How the prev rounds were. What I know about payu. Relocating, CTC, workin days etc.
Recommended Reading: geeksforgeeks.org/data-structures, headfirst for java, os video lectures by pk biswas.
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