Coding questions
IOCL Online Assessment
Overview
Here is how public prep guides and student write-ups describe the IOCL online assessment. This is not an official company brochure.
Official PSU CBT with published sectional structure and category cutoffs - not a private IT OA.
Usual selection rounds
Rounds students usually mention: Computer Based Test (CBT) → Group Discussion / Group Task → Personal Interview
| Item | From student reports |
|---|---|
| Platform | CBT |
| Online test summary | Official Grade E0-style ad: 100 MCQs - Domain 50 + General Aptitude (Quant 20, LR 15, Verbal 15). Sectional and overall qualifiers by category. |
| Eligibility notes | As per specific notification (percentage/grade rules in official ads) |
| Branches (reported) | Domain-wise as per advertisement |
Online test sections
| Section | Questions | Time | Notes |
|---|---|---|---|
| Domain knowledge | 50 | part of total CBT duration in ad | Section A |
| Quantitative aptitude | 20 | - | Section B |
| Logical reasoning | 15 | - | - |
| Verbal ability | 15 | - | - |
Extra notes from sources
- General/EWS/OBC-NCL: 40% each in A and B and 45% overall to qualify CBT (per cited ad).
- SC/ST and PwBD have lower listed qualifiers in the same ad.
- Always download the current vacancy PDF - patterns change by post.
Sample practice question styles
These are practice questions for speed - not claimed to be from a real IOCL live paper.
Coding Q1: Linked list cycle
Problem: Given the head of a linked list, return true if there is a cycle and false otherwise.
Approach: Floyd’s tortoise and hare: move one pointer one step and another two steps. If they meet, a cycle exists. If the fast pointer hits null, there is no cycle.
Complexity: O(n) time, O(1) space
IOCL tip: Restate the problem, sketch a brute-force idea, then tighten it. Call out edge cases (empty input, single element, overflow) before you write code.
Coding Q2: Binary tree level order
Problem: Given the root of a binary tree, return the level-order traversal (breadth-first) as a list of levels.
Approach: Use a queue. For each level, drain the current queue size, collect values, and enqueue children for the next level.
Complexity: O(n) time, O(n) space
IOCL tip: Restate the problem, sketch a brute-force idea, then tighten it. Call out edge cases (empty input, single element, overflow) before you write code.
Coding Q3: Coin change (min coins)
Problem: Given coin denominations and an amount, return the fewest coins needed to make that amount, or -1 if it is impossible.
Approach: Unbounded knapsack DP: let dp[x] be the minimum coins for amount x. For each coin, update dp[c..amount]. Initialize dp[0] = 0 and the rest to a large sentinel.
Complexity: O(amount × coins)
IOCL tip: Restate the problem, sketch a brute-force idea, then tighten it. Call out edge cases (empty input, single element, overflow) before you write code.
Coding Q4: Binary search
Problem: Given a sorted array of distinct integers and a target, return the index of target or -1 if missing.
Approach: Maintain lo/hi. Compare mid with target and shrink the half that cannot contain it. Careful with overflow-free mid and empty arrays.
Complexity: O(log n) time
IOCL tip: Restate the problem, sketch a brute-force idea, then tighten it. Call out edge cases (empty input, single element, overflow) before you write code.
Prep tips from those student reports
- Download the exact notification PDF for your post
- Balance domain 50 + aptitude 50
- Practice GD/GT for PSU panels
Sources
These notes come from public reports and can differ by campus, year, and role. If your college placement email or the official careers/notification PDF says something different, follow that.