Amazon Interview | Set 62 (For SDE-1)

I recently went through the Amazon interview process for the post of SDE-1.

Round 1 (Written)
1. Given an array, output an array where every index conains nearest greatest element to that element on right side.
2. Program to convert sorted array to Binary Search Tree
3. Find first non-repeating character in String
ex: geeksforgeeks: f
geeksforgeeksFirst:o

Round 2 (F2F)
1. Given linked list as a-x-b-y-c-z
output it as a-b-c-z-y-x
that is reverse alternate element and append to end of list

2. Output nearest number greater than given number such that output is palindrome
ex: 121:131
900:909
99:101

Round 3 (F2F)
1.https://www.geeksforgeeks.org/problems/vertical-sum/1( I told him I know the solution, he proceeded further)
2. Given stream of Strings find top 5 words with maximum frequency or count
3. Given 2 nodes in Binary Tree find distance between them

Round 4 (F2F with hiring manager)
1. Projects done so far, HR questions
2. Design Linkedin and find till 2nd level connections and path between 2 connection
for ex: if A is friend of B which is friend of C
print between A and C A-B-C
3. Programming language: Java
About synchronisation, serialization, transient and volatile keyword, Singleton Class

Round 5 (Bar Raiser)
1. Count Inversion in array that is if i a[j]
Told the solution nlogn of divide and conquer. He asked another solution, then told by inserting in BST and whenever node goes to left side then adding 1 and number of children on right side . We have to keep track of count of right subtree in every node

Round 6 (F2F)
1. HR questions (Why leaving company, projects, SWOT)
2. Program to check for mirror tree
3. Data Structure so that push, pop, getmin, getmax O(1) (using 3 stacks)
4. Data Structure so that push, pop, pop min, pop max
Told Solution till O(logn) by using min heap, max heap with pointers to doubly linked list nodes

All Practice Problems for Amazon !