Coding questions
BPCL Online Assessment
Overview
Here is how public prep guides and student write-ups describe the BPCL online assessment. This is not an official company brochure.
Oil PSU - based on the official recruitment notice.
Usual selection rounds
Rounds students usually mention: CBT / GATE path as notified → GD/Interview as notified
| Item | From student reports |
|---|---|
| Platform | Official CBT/GATE |
| Online test summary | Like other oil PSUs, pattern is advertisement-specific (domain + aptitude style papers common). Use BPCL PDF, not IT blogs. |
| Eligibility notes | As per notification |
| Branches (reported) | As per post |
Online test sections
Section-level detail not verified in our source set yet - use the placement email / official PDF.
Extra notes from sources
- Check your college placement email for the platform, section order, and timing.
Sample practice question styles
These are practice questions for speed - not claimed to be from a real BPCL live paper.
Coding Q1: Valid parentheses
Problem: Given a string containing only ‘()[]’, decide whether the brackets are balanced and correctly nested.
Approach: Scan left to right with a stack. Push opening brackets. On a closing bracket, the stack top must be the matching opener. At the end the stack must be empty.
Complexity: O(n) time, O(n) space
BPCL 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: Two Sum
Problem: Given an array of integers and a target, return indices of two numbers that add up to the target. Assume exactly one solution and you may not use the same element twice.
Approach: Walk the array once. For each value x, check whether target − x was seen earlier in a hash map of value → index. If yes, return both indices; else store x.
Complexity: O(n) time, O(n) space
BPCL 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: Longest substring without repeating characters
Problem: Given a string s, find the length of the longest substring without repeating characters. Example: ‘abcabcbb’ → 3 (‘abc’).
Approach: Sliding window with a map (or last-seen index) of characters. Expand the right pointer; when a duplicate appears inside the window, move the left pointer past the previous occurrence.
Complexity: O(n) time
BPCL 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: Merge overlapping intervals
Problem: Given a list of intervals [start, end], merge all overlapping intervals and return the non-overlapping set that covers the same ranges.
Approach: Sort by start time. Walk once, merging into the last interval in the result when the next start is ≤ current end; otherwise append a new interval.
Complexity: O(n log n) time from the sort
BPCL 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
- Official ad
- Domain + aptitude
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.