# One97(Paytm) Interview Experience

• Difficulty Level : Expert
• Last Updated : 28 May, 2019

Written 1: Technical and Aptitude.
Written 2: Written Coding

• Written 1 was Normal Written exam based on fundamentals of Aptitude and Computer Science.
• Written 2:
Few Questions I remembered :

Q1:

```
char a;
int i = 300;
a = &i;
a++;
*a=2;
printf("%d",i); ```

Q2:

``` Imagine you have a special keyboard with the following keys:
A
Ctrl+A
Ctrl+C
Ctrl+V ```

where CTRL+A, CTRL+C, CTRL+V each acts as one function key for “Select All”, “Copy”, and “Paste” operations respectively.
If you can only press the keyboard for N times (with the above four keys), please write a program to produce maximum numbers of A. If possible, please also print out the sequence of keys.
That is to say, the input parameter is N (No. of keys that you can press), the output is M (No. of As that you can produce).

Q3: Consider a Binary Tree not necessarily BST, Remove all nodes which don’t lie in any path with sum>= k.

Q4: Given an array arrange it in the form a<b>c<d>e<f>g……….

Q5: Given an array of numbers arrange it in the form of a single number such that the concluded number is
the maximum.
e.g. given : 99, 8, 76, 45, 66, 9, 7, 33, 5, 42
O/P : 99987766654233

Sectional Cut-off for O/P and Coding Questions.
Marking was done against the correct approach, not the exact answers.

• Round 1 (Technical):
Q1: How will you store 800 Million records in database.
Q2: Data storage of double and float differs in C/C++ and Java How is it ???
Q2: Transfer data between a program written in Java and C#.
Q3: I need to establish a network in which I will be sure of security, How will you proceed
Q4: A and B are two sets Write a non-nested query so that I can get the data in B but not in A.
Q5: 000…………..? 11111111111111111111…………….? Write a Program which finds the index of the
start of series 11111111…..?.

• Round 2 (Technical):
Q2: Explain your project “Stock Prediction”
Q3: I want to retrieve records from a table from date 1 – 15. I don’t want to use range Queries
Suggest optimal solutions…
I suggest Indexing on the date column.
He insisted on alternate ways.
“he said what you think you can do……”
Q4: What is Unique and NULL Constraint?
Difference between Primary Key and Unique.
How many maximum records in Unique can be NULL?
Q5: Write the Most optimized algorithm for finding a Word in the sentence.
(I used the Trie approach, he scolded me for not asking the sentence is sorted or not. the used Binary search.)
Q6: Difference between thread and process.
What is PCB?
What is synchronization ??
What is Semaphore?
Explain and solve the Producer-Consumer Problem using Semaphore? What is Drawback here
What is the monitor? Solve Producer-Consumer Problem using Monitor and explain the pros and cons.

Final 8 candidates from Delhi region selected.

• Round 3(Final Round Managerial and Technical):
Q1: What you want to do in your Life ?? Discussion life as a placement coordinator?
Q2: Doing Post Market Analysis of a Stock Market of Previous Month.
Write a Program of Stock Buy Sell to Maximize Profit.
Q3: Explain Cursor ? its types? differences between them? What to use when?
Q4: Explain Matrix? Matrix Multiplication? Difference ways of Matrix Multiplication? Explain Both.
Q5: What are you doing right now ??? will you join us ?? Why ??

Students from 30 Colleges of India are evaluated and Top 25 are offered the JOB.

I was not one of them.

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