Just went through the McDonald's Global Technology online assessment for a new grad / junior SWE role. Sharing details because I couldn't find much when I was prepping.
Platform: HackerRank (or HackerRank-style, might vary by role)
Format I got: 2 coding problems, 75 minutes total. There was also a 10-question multiple choice section at the start covering CS fundamentals (Big O, data structure properties, one SQL question). Multiple choice was maybe 10 minutes.
Difficulty: Problem 1: LeetCode easy-medium. Array manipulation, find the subarray with max sum. Straightforward if you know Kadane's algorithm. Problem 2: LeetCode medium. String parsing / sliding window. Had a constraint that made naive approaches fail.
Neither problem was LeetCode hard territory. But the 75 minute window felt tight because I spent too long reading the MC section carefully. Skim that first, then budget your coding time.
What I wish I'd known: Know your complexity analysis cold. They explicitly asked for time and space complexity in comments. The SQL fundamentals question was basic JOIN, nothing fancy. Just know how to write a LEFT JOIN. Edge cases matter. One test case was specifically checking empty input and I initially skipped it.
I passed the OA and moved to a technical phone screen. The phone screen was one more problem, medium difficulty, explained via screenshare. They actually let me code in my own IDE which was nice.
Overall the OA felt more approachable than the Amazon or Google OAs I've taken. Solid medium prep should be enough. Don't overthink it.