Coding questions
Siemens Online Assessment
Overview
Here is how public prep guides and student write-ups describe the Siemens online assessment. This is not an official company brochure.
Reported C-output technical OA plus extremely time-compressed aptitude section.
Usual selection rounds
Rounds students usually mention: Online technical test → Online aptitude test → Technical interview → HR interview
| Item | From student reports |
|---|---|
| Platform | Online tests |
| Online test summary | FACE Prep: technical test 30Q/30min focused on C pointers/output/DS; aptitude 24Q/18min quant+verbal+logical. |
| Eligibility notes | FACE Prep fresher guide: 7.5 aggregate CGPA, 60% in 10th/12th, no active backlogs (verify - other Siemens guides cite ~6.5-7.0 for some software roles) |
| Branches (reported) | CSE/IT for software; ECE/EEE/instrumentation for automation tracks |
Online test sections
| Section | Questions | Time | Notes |
|---|---|---|---|
| Technical (C-focused) | 30 | 30 min | Pointer arithmetic, memory, output prediction, basic DS in C |
| Aptitude | 24 | 18 min | Quant, verbal, logical - very tight timing |
Extra notes from sources
- Some write-ups merge technical+aptitude differently; college placement email wins.
Sample practice question styles
These are practice questions for speed - not claimed to be from a real Siemens live paper.
Coding Q1: Move zeros
Problem: Move all zeros in an array to the end while keeping the relative order of non-zero elements.
Approach: Two pointers: write non-zeros toward the front, then fill the remainder with zeros. Or swap zeros as you scan.
Complexity: O(n) time, O(1) space
Siemens 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: Rotate array
Problem: Rotate an array to the right by k steps. Example: [1,2,3,4,5,6,7], k = 3 → [5,6,7,1,2,3,4].
Approach: Normalize k %= n. Reverse the whole array, reverse the first k elements, then reverse the rest. That yields the rotation in place.
Complexity: O(n) time, O(1) space
Siemens 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: First unique character
Problem: Find the first non-repeating character in a string and return its index, or -1 if none exists.
Approach: Count frequencies in one pass (hash map or array of 26 for lowercase). Second pass returns the first index with count 1.
Complexity: O(n) time
Siemens 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: Stack with min
Problem: Design a stack that supports push, pop, top, and getMin in average O(1) time.
Approach: Keep a parallel min-stack (or store pairs). When pushing, also push the new minimum. When popping, pop both stacks.
Complexity: O(1) per operation amortized
Siemens 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
- Drill C pointers and output prediction under 1 min/question pace
- Aptitude speed (≈45 seconds/question in the 24/18 pattern)
- Match prep to software vs automation JD
Sources
- Siemens Recruitment Process 2026 - FACE Prep (faceprep)
- Siemens Interview Questions - FACE Prep (faceprep)
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.