ARM OA Experience 2026 | 90 Minutes | Aptitude + Technical + 2 Coding Questions

I recently gave the ARM Online Assessment and wanted to share the pattern and all the questions I can remember. Hopefully this helps others preparing for ARM.

The overall structure was quite similar to the Texas Instruments OA pattern.

OA Pattern

Total Duration: 90 minutes

Section 1: Aptitude

• 15 Questions
• 20 Minutes

Section 2: Technical

• 30 Minutes

Section 3: Coding

• 2 Coding Questions
• 40 Minutes

Coding Questions

Coding Question 1 – Consecutive Sum of K Positive Integers

We were given:

S, E, K

We had to find numbers in the inclusive range:

[S, E]

such that the number could be represented as the sum of K consecutive positive integers and also satisfied the required divisibility condition with K.

We then had to return/count the numbers satisfying the conditions.

The main idea involved understanding when a number can be represented as:

x + (x+1) + (x+2) + ... + (x+K-1)

for some positive integer x.

The sum becomes:

K*x + K*(K-1)/2

So this question was mainly based on:

• Mathematics
• Consecutive integer sums
• Divisibility
• Range checking

Coding Question 2 – Number to Encoded Character

We were given an integer:

1 <= X <= 1000

and had to return an encoded alphabet character.

Examples I remember:

1 -> C
2 -> F

The alphabet positions were considered as:

A = 1
B = 2
C = 3
...

The encoding logic involved adding something like:

2 * X

to the original value.

So:

X = 1

1 + 2*1 = 3
3 -> C

and:

X = 2

2 + 2*2 = 6
6 -> F

For larger values, the alphabet encoding had to be handled according to the rule given in the question.

Aptitude Questions I Remember

1. Calendar Question

If the 18th day of a month is Tuesday, what day of the week was the 1st day of that month?

2. Data Interpretation

There were around 2–3 questions based on a graph.

Questions involved interpreting values, percentages, comparisons, etc.

3. Odd/Even Numbers

Given:

a × b = odd

Which of the following is true?

Options were similar to:

• a + b is even
• a - b is even
• a and b are both odd
• All of the above

4. Series / Pattern

Find the next term:

Z2, X4, V8, T16, ___ ?

This involved identifying patterns in both:

• Alphabet positions
• Numbers

5. Circular Seating Arrangement

There were around 4–5 questions based on a single circular arrangement.

Several people were seated in a circle and we had to determine:

• Who sits opposite whom
• Who sits next to whom
• Position relative to another person
• Possible/definite arrangements

6. Age Problem

A question was based on the age difference between S and R.

The information was something similar to:

• Difference between the ages of S and R was given.
• When R was born, S was around 28 years old.
• We had to calculate the current age of S using the remaining information given in the question.

7. Boats and Streams

One question was based on:

• Upstream speed
• Downstream speed

So revise formulas:

Downstream = Boat Speed + Stream Speed
Upstream   = Boat Speed - Stream Speed

8. Probability – Three Digit Number

A probability question asked about forming a three-digit number satisfying conditions similar to:

• It contains exactly one odd digit
• The number is divisible by 5

We had to find the probability of such a number.

Technical Questions

9. AVL Tree Rotations

A sequence of numbers was given and we had to construct an AVL Tree.

The question asked:

How many rotations are required while inserting the given numbers?

Important concepts:

• LL Rotation
• RR Rotation
• LR Rotation
• RL Rotation
• Balance Factor

10. Postfix Expression Evaluation

A postfix expression was given similar to:

23 16 72 51 -3 1 6 1 7 8 + - + *

and we had to calculate the final output.

This required evaluating the postfix expression using a stack.

11. Pattern Printing – Missing Code Line

A star pattern was given similar to:

  *
 ***
*****
 ***
  *

Some code was already provided and we had to select the missing line of code needed to generate the pattern correctly.

So output tracing and loop conditions were important.

12. Dynamic Programming Output Question

There was an output-based question on Dynamic Programming.

A code snippet was given and we had to trace the DP array/table and determine the final output.

13. C/C++ Output Questions

There were around 2–3 more output-based questions.

These required carefully tracing the program rather than writing code.

Good topics to revise:

• Loops
• Arrays
• Increment/decrement operators
• Conditions
• Recursion
• Pointer/array behaviour
• Operator precedence

14. Circular Queue

There were questions based on Circular Queue.

Important concepts:

front
rear
enqueue
dequeue
overflow
underflow

and conditions such as:

(rear + 1) % size == front

for detecting a full circular queue.

Topics I Would Recommend Revising for ARM OA

Aptitude

• Calendar
• Probability
• Permutation and Combination
• Boats and Streams
• Ages
• Number Series
• Alphabet Series
• Circular Arrangement
• Data Interpretation
• Odd/Even properties
• Divisibility

Data Structures

• AVL Tree
• BST
• Stack
• Postfix Evaluation
• Circular Queue

Programming

• C/C++ Output Questions
• Loops
• Pattern Printing
• Operator Precedence
• Arrays
• Dynamic Programming

Coding

• Mathematical observations
• Divisibility
• Range-based problems
• Consecutive integer sums
• Character/ASCII encoding
• Modular arithmetic

Overall Experience

The biggest challenge was time management.

The aptitude section had:

15 questions in 20 minutes

so there was not much time to spend on any single question.

The technical section had several questions where knowing the concept was not enough — you also needed to quickly trace code, evaluate expressions, or construct data structures.

The coding section had 40 minutes for 2 questions, and both questions seemed much easier once the mathematical observation or encoding logic was identified.

For anyone preparing for ARM, I would especially recommend practicing:

Aptitude + C/C++ output questions + AVL Trees + Stack/Postfix + Circular Queue + basic DP + mathematical coding problems.

These are all the questions I can currently remember from the OA.