Ola Electric Interview Experience

Ola Electric Interview Experience

Round 1
Q1 Print a matrix in zig zag fashion?
Solution



Round 2
Q1 Discussion on different authentication mechanisms? Bearer, oAuth, JWT

Q2 Difference between authentication and authorization

Q3 Given array { 1 2 3 4 5 6 7 8 9 10 } print { 2 3 7 8 9 10 }
Skip 1, print next 2, skip next 3, print next 4

Q4 Stream of numbers are coming and a camera is recording them but the output from camera is rotated by 180 degree. How many numbers are same as 180 degree rotation of the original number. Write program to print those numbers? You need to identify all the possible test cases before writing the code.

0, 1, 6, 8 and 9 are same as 180 degree rotation.
Ex 69, 689, 121, 11


Round 3
Q1 Spring Bean life cycle

Q2 What is a java bean?
JavaBeans are classes that encapsulate many objects into a single object (the bean). It is a java class that should follow following conventions:
Must implement Serializable.
It should have a public no-arg constructor.
All properties in java bean must be private with public getters and setter methods.

Q3 What is IOC, Dependency Injection

Q4 How Autowired works in Spring

Q5 Difference between Component, Service and Repository

Q6 How will you handle horizontal partitioning in mysql database?

Q7 System design of Twitter


Round 4
Q1 System design of uber payments.

Q2 Given an n*m matrix. Write a program to print the min path from source to destination such that you can move only right and down and if there are 'X' in the path then you cannot cross that path.
[S       ]
[ X X ]
[   X   ]
[      D]

Solution