SDE - 1

There were questions regarding SQL queries, ACID properties in DBMS and Normalisation forms specially 3NF and BCNF.

Questions were around 
1. memory management
2. paging
3. CPU scheduling (numerical questions) like First come First serve, Round Robin scheduling etc.

Questions were around 
1. TCP vs UDP
2. DNS system
3. SMTP SNMP protocol.

Questions were around 
1. Java memory management, 
2. Garbage collection, 
3. a few code snippets asking the output of a code, 
4. polymorphism, 
5. thread synchronisation - theory as well as 1 code snippet.

Questions were around 
1. unordered map vs map, 
2. asymptomatic complexities of a few code snippets, 
3. DFS vs BFS in a graph, 
4. order of complexity for different sorting techniques like bubble sort merge sort etc.

You are given a Binary Tree.

Return the length of the diameter of the tree.

Note :

The diameter of a binary tree is the length of the longest path between any two end nodes in a tree.

The number of edges between two nodes represents the length of the path between them.

Example :

Input: Consider the given binary tree:

Output: 6

Explanation:
Nodes in the diameter are highlighted. The length of the diameter, i.e., the path length, is 6.

You have been given a matrix of ‘N’ rows and ‘M’ columns filled up with integers. Find the minimum sum that can be obtained from a path which from cell (x,y) and ends at the top left corner (1,1).

From any cell in a row, we can move to the right, down or the down right diagonal cell. So from a particular cell (row, col), we can move to the following three cells:

Down: (row+1,col)
Right: (row, col+1)
Down right diagonal: (row+1, col+1)

Questions were around:
1. Explain abstraction and encapsulation with an example
2. What are design patterns? There was a small discussion around Builder Design Pattern
3. How hashmap internally works?
4. What are singleton classes? How can we make a class as singleton

1. Was there any instance when you had to incorporate last minute changes as per customer requirement. How did you handle it?
2. Why do you want to join Paytm?
3. Was there any situation when you had to take up some challenges outside of your domain?
4. Tell any one strength and one area of improvement

1. Difference between equals and == operator in Java
2. Why string in Java is immutable
3. What are checked and unchecked exceptions with example.