Status: 4th year CSE student at Tier-2 college
Position: SDE1 at Amazon
Location: India
Date: Feb 15th 2022
Opportunity type: Offcampus

Round 1: 1st Technical Round

1. Short Introduction

2. Minimum operations needed to balance a parenthesis string. We can either insert a paranthesis or replace an existing one with another. Each operation costs 1 unit.

   Example: "))(((" , "(()(("

   I used a stack to keep track of all the unbalanced paranthesis like "))(" and count them. If the count is even then the answer is n/2 else (n/2) + 1.

3. Given a binary tree and value V and level L, insert the values V at the Lth level of the tree in the same structure as the existing level L

   Example:

    	 1        Level 1
    	/ \
      2    3     Level 2
     /      \
    4        7   Level 3
   
     V = 10, L = 3
     
     Output:
   
    	  1        Level 1
    	 / \
       2    3     Level 2
      /      \
     10      10   Level 3
    /          \
    4           7 Level 4

   I did a level order traversal up to the L-1th level with my queue storing all the nodes in the Lth level. Then I inserted new nodes having values V and added their appropriate child node

Solved both questions, first one took me 20-25 minutes to code and explain. Second question also took me around the same time.

Round 2 experience:
https://leetcode.com/discuss/interview-experience/1925974/Amazon-SDE-1-or-New-Grad-2022-or-India-or-Apr-2022-or-Round-2