EPAM Systems Software Development Engineer SDE interview questions

I recently interviewed for an SDE role at EPAM Systems, and overall the process was quite difficult and very technical. The interview process had multiple rounds focused heavily on problem-solving, DSA, core CS fundamentals, and practical coding ability. The coding rounds were tougher than I expected — not just standard LeetCode-style questions, but also follow-up optimizations, edge cases, and discussions around time and space complexity. The interviewers kept pushing deeper whenever I solved something quickly. One of the challenging parts was that they didn’t just want a working solution; they expected clean code, good communication, and strong reasoning throughout. I was asked to explain trade-offs, optimize approaches, and sometimes even redesign the solution midway based on new constraints