[New Grad] SK AX (formerly C&C) - Coding Test & Interview (Final Acceptance) Review

Hi! Sharing my most recent acceptance review.

I currently work at this company. Here's a review of the SK Inc. AX (formerly C&C) new graduate coding test and interview. As always, I'll avoid anything that touches on company security.

I applied for SK Inc. AX (formerly C&C) 2023 H2 new graduate SW hiring.

The 2023 H2 schedule was as follows:

Figure 1. Document screening — passed

Since the document screening varies by background and motivation, I'll skip that and go straight to the coding test / SKCT / interview review.

Coding test + SKCT (psychological)

Date: 2023-10-22 (Sunday)

• Coding test: 09:00 ~ 11:00 (2 hours)
• SKCT (psychological): 13:00 ~ 14:30 (1h 30m)

The coding test had 4 problems — 3 algorithm + 1 SQL. I'll write out what I remember about the types of problems.

⚠️ I'm reconstructing from memory, so this isn't 100% accurate.

Problem 1 (implementation) — moving a mouse across monitors

Figure 2. My hand-drawn reconstruction of problem 1

Setup

You're given monitors with different widths and heights. Each monitor's coordinates are measured from the bottom-left as (0,0). Multiple monitors exist, and the mouse pointer has a starting position.

• All coordinates are row/column distances from each monitor's (0,0)
• The mouse can move between monitors. When it crosses into another monitor, the coordinates are measured from that monitor's (0,0)

Given

The monitor (number) where the scenario starts and the starting coordinate on that monitor. Then N mouse-move commands (r_move, c_move) from the current coordinate.

Requirement

After applying all N move commands, return the current monitor's number and the coordinate within that monitor.

My scenario example

If the current coordinate is (100, 200) on Monitor 3 and the move command is (-200, -300), you can't go below the monitor (clamped to 0), so the result would be Monitor 2 at (200, 0).

Problem 2 (dynamic programming) — find the minimum

I couldn't come up with the recurrence and skipped it immediately.

Problem 3 (implementation) — moving in all directions, full cycle

Figure 3. Left (a), right (b). Hand-drawn reconstruction.

Direction changes based on the letter on each cell: S, R, L.

• S: keep going
• R: turn 90° clockwise from current direction
• L: turn 90° counter-clockwise from current direction
• If you hit a wall, reverse direction (180°).

Start at the top-left (0,0), heading down. So in figure (a), it's heading down and S means keep going down. In (b), it's L so it turns right.

Requirement: return the number of visited cells.

A previously visited cell doesn't count again (but you can still pass through it). The scenario ends when no new cells are being visited.

• (a) visits all 25 cells and terminates
• (b) loops infinitely on some cells, so you need a termination condition — return 9.

→ Termination condition was tricky.

Problem 4 (cumulative sum) — SQL

Figure 4. Hand-drawn SQL problem table

Problem: Given daily sales for a month, compute cumulative sales in SQL.

Coding test summary

4 problems in 2 hours was tougher than I expected. I hadn't done cumulative sum in SQL before, so I got stuck a lot.

⚠️ Problems change every cycle, so treat this as "this is roughly the difficulty level that round."

SKCT is SK's psychological screening — like any personality test, just answer consistently with yourself. It's online so not stressful, and I actually finished earlier than the 1h 30m allotted.

Figure 5. Written test stage — passed

I passed the written stage (coding test + psychological) and moved on to the interview.

1-Day Interview

Discussion interview + Job/Personality interview

🔒 I can't reveal the topic of the discussion interview or the pre-assignment for the job interview.

The discussion and job/personality interviews happen on the same day. I'll cover both formats.

When you arrive, the cohort is split in half — some do the job/personality interview first then discussion, others do discussion first then job/personality. e.g. 16 people → 8 go (1) job/personality → discussion, the other 8 go (2) discussion → job/personality.

I did the discussion first, so I'll start there.

1. Discussion interview

Goal

A problem situation is given, and within the allotted time you have to negotiate to reach an agreement.

Setup

The moment 8 of you enter, papers with the problem situation are on the desk. You read it and split into Team A / Team B. Even that splitting process is part of the interview — you have to negotiate. After splitting in half, you start the discussion.

The problem is set up so A and B have opposing positions, and each side has to negotiate to maximize their score. The negotiation dimensions (4–5 of them) are clearly listed in a Table, and you negotiate based on that Table to secure better scores for your team.

Everything — from coordinating opinions to the actual discussion — is being assessed. There's also a per-person evaluation at the end.

📝 The interviewers continuously take notes and record while you discuss. From the moment the interviewer's explanation ends, assume everything is being evaluated.

Discussion interview summary

Personally, I thought the discussion interview was fun. Time flew, and as a side effect, all my nerves were gone by the time the job/personality interview started — I went in totally relaxed.

2. Job/Personality interview

For the job/personality interview, after passing the coding test, you're given a pre-assignment on a specific topic. You write a 2-page PPT (3 with cover) based on your reasoning and submit it. In the interview room, your PPT is projected, and you present for about 10 minutes in front of the interviewers.

After presenting, the interviewers ask questions and you defend your reasoning. If your presentation was great, sometimes there are no follow-up questions — don't panic if that happens. Just present and answer with conviction.

After the presentation, job or personality questions follow. In my case, the tech stack at my previous job overlapped a lot, so they barely asked job-related questions. They did probe my reasons for moving as a junior re-hire (within 2 years of starting). That's a question anyone moving as a junior re-hire should be ready for — I defended it well. Then they asked more about my values and philosophy on specific industries, team collaboration, work style, etc.

I treated it like a deep conversation with a friend — answered sincerely, no pressure. The interviewers were really friendly, which helped me relax even more (they really are friendly).

📝 Job/personality interview is many-to-many — 2 candidates and 3 interviewers in our session.

Job/personality interview summary

I think I really nailed the presentation and conveyed about 99% of what I wanted to say. No regrets, and I could roughly tell I'd pass.

💰 Oh — they pay you an interview fee when you show up!

After the interviews, I waited for the result, which came on 2023-12-05. As I roughly expected — accepted. No matter how much you expect it, an acceptance result is always sweet :)

Figure 6. Final result — accepted

And that's the full journey of the SK C&C new graduate hiring process, ending with my joining the company.