I’m a 3rd year grad and amazon visited our campus. My interview had only 3 rounds.
Round 1 (Online round 20 MCQ’s and 2 coding questions )
MCQ’s were mostly on data structures ,time complexities and C,C++ outputs with 2 aptitude questions.
1) Given 2 linked lists of digits as data in their nodes add two numbers.
Eg: 1 -> 2 -> 3 -> 4 and 4->3 print 1 - > 2 -> 7 -> 7
Eg: Input : (5,7) (1 , 6) (2 ,4) (10 ,14) (8,9) Output : (1,7) (8,9) (10,14)
Round 2 (F2F)
Tell me something about yourself.
1) Convert a BST into inorder, preorder and postorder linkedlists inplace.
2) Make a queue out of 2 stacks, as it was easy he asked me to code and asked me the complexities.
He asked me I had any questions.
Round 3(F2F) (After lunch)
1) Given a Binary tree convert into a BST no auxiliary space (i did it with an inorder traversal) he asked me to code.
2) Given an infinite stream of characters find the first non repeating character at any instance , The storing,retrieval should be o(1) .
I told him a solution using a hashmap then he modified that he may have millions of unique characters not just alphabets.
i gave a solution with a linked list and a hashmap. This question was not asked to me but was to my friend .Its a good one.
3) print all the binary values of number from 1 to n , each number’s binary should be printed in 0(1).
for eg: n = 6
then print 1 10 11 100 101 110. printing 1, 10 ,11 ,100,101,110 should be in o(1) each
I thank Geeksforgeeks for letting me know about Floyd’s cycle .
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