Associate Software Engineer

You have 8 balls, one of which is heavier. Using a weighing balance, find the heavier ball in minimum attempts.

A clock shows the time as 3:15. What is the angle between the hour and the minute hand?

Two trains are 120 km apart and move towards each other at speeds of 60 km/h and 40 km/h. A bird starts flying from one train to the other at 80 km/h until the trains meet. Find the total distance covered by the bird.

There are 100 doors initially closed. A person toggles doors in the following way: toggles every door in the first pass, every 2nd door in the second pass, every 3rd in the third pass, and so on till the 100th pass. Which doors remain open?

A man walks 1 km south, 1 km east, and 1 km north and comes back to the same point. How is this possible?

Which scheduling algorithm may cause starvation?

Consider 3 processes with burst times 10, 5, and 8. Calculate the average waiting time using FCFS scheduling.

Which of the following is not true about deadlock? 
a) Mutual exclusion is a necessary condition 
b) Hold and wait must exist 
c) Circular wait must exist 
d) Deadlock can always be resolved using FCFS

In demand paging, what happens on a page fault?

Which of the following is true about thrashing?
a) It increases CPU utilization
b) It occurs due to excessive paging
c) It reduces I/O time
d) It improves performance

Consider a relation R(A,B,C,D) with functional dependencies:
A → B, B → C. What is the highest normal form?

Which of the following ensures atomicity in transactions?
a) Commit log
b) Checkpoint
c) Transaction log
d) Deadlock prevention

Given the SQL query:
SELECT name FROM Student WHERE marks > ALL (SELECT marks FROM Student WHERE dept = 'CSE');
What does it return?

Which of the following indexing techniques is used in databases for faster access?
a) Hashing
b) B+ Tree
c) Both a & b
d) None

In two-phase locking protocol, which problem can still occur?
a) Deadlock
b) Lost update
c) Dirty read
d) Non-repeatable read

You are given an array 'a' of size 'n' and an integer 'k'.

Find the length of the longest subarray of 'a' whose sum is equal to 'k'.

Example :

Input: ‘n’ = 7 ‘k’ = 3
‘a’ = [1, 2, 3, 1, 1, 1, 1]

Output: 3

Explanation: Subarrays whose sum = ‘3’ are:

[1, 2], [3], [1, 1, 1] and [1, 1, 1]

Here, the length of the longest subarray is 3, which is our final answer.

You are given the root node of a binary tree.

Return 'true' if it is a height balanced binary tree.

Note:

Height of a tree is the maximum number of nodes in a path from the node to the leaf node.

An empty tree is a height-balanced tree. A non-empty binary tree is a height-balanced binary tree if
1. The left subtree of a binary tree is already the height-balanced tree.
2. The right subtree of a binary tree is also the height-balanced tree.
3. The difference between heights of left subtree and right subtree must not more than ‘1’.

Example:

Input: Consider the binary tree given below:

Output: 'true'

Explanation:
Consider subtree at Node ( 7 ) 
Left subtree height is ‘0’ and right subtree height is ‘0’, the absolute height difference is ‘0-0 = 0’ and ‘0’ is not more than ‘1’ so subtree at Node ( 7 ) is a height-balanced binary tree. 
Same for subtrees at Nodes ( 5, 6 ). 

Consider subtree at Node ( 4 ) 
Left subtree height is ‘1’ and right subtree height is ‘0’, the absolute height difference is ‘1-0 = 1’ and ‘1’ is not more than ‘1’ so subtree at Node ( 4 ) is a height-balanced binary tree.
Same for subtree at Node ( 3)

Consider subtree at Node ( 2 ) 
Left subtree height is ‘2’ and right subtree height is ‘1’, the absolute height difference is ‘2-1 = 1’ and ‘1’ is not more than ‘1’ so subtree at Node ( 2 ) is a height-balanced binary tree.

Consider subtree at Node ( 1 ) 
Left subtree height is ‘3’ and right subtree height is ‘2’, the absolute height difference is ‘3-2 = 1’ and ‘1’ is not more than ‘1’ so subtree at Node ( 1 ) is a height-balanced binary tree.

Because the root node ( 1 ) is a height-balanced binary tree, so the complete tree is height-balanced.