CME Group coding interview
questions, leaked.
2 problems reported across recent CME Group interviews. Top patterns: string, trie, array. The list below is what most reported candidates actually saw, plus the honest play if you can't grind all of it.
CME Group's coding assessment is lean but deceptive. Two problems, both easy on the surface, but they're testing core patterns you can't fake under pressure. One hits string manipulation and trie logic; the other forces you to think about state transitions across an array. You've got days to drill these patterns cold. If you blank on either during the live assessment, StealthCoder runs invisibly and surfaces a working solution in seconds, keeping you moving forward.
Top problems at CME Group
| # | Problem | Diff | Frequency | Pass % | Patterns |
|---|---|---|---|---|---|
| 01 | Longest Common Prefix | EASY | 100.0 | 45% | String · Trie |
| 02 | Best Time to Buy and Sell Stock | EASY | 83.9 | 55% | Array · Dynamic Programming |
Frequencies derived from public community-tagged interview reports. Click a row to view on LeetCode.
You have a week, maybe less. You can't out-grind the list above. StealthCoder runs invisibly during the actual CME Group OA. The proctor cannot see it. Screen share cannot detect it. Made for the engineer who has done the work but might still blank with a webcam pointed at him.
Get StealthCoder- string1 · 50%
- trie1 · 50%
- array1 · 50%
- dynamic programming1 · 50%
The distribution is split evenly: one string/trie problem, one array/dynamic-programming problem. Both are easy, which means CME isn't filtering on complexity. They're filtering on clarity of thought and clean code. Trie problems trip people up because the data structure feels abstract until you've built one from scratch. The stock-trading problem looks deceptive easy but requires you to track state across iterations, which candidates often mess up under time pressure. Drill the trie construction first (it's the less intuitive pattern), then run through multiple stock variants to lock in the state-tracking logic. StealthCoder is your hedge if the trie implementation gets fuzzy mid-OA.
Companies with similar patterns
If you prepped for CME Group, these companies recycle ~60% of the same topics.
You've seen the list.
Now make sure you pass CME Group.
Memorizing every problem above in a week is a fantasy. StealthCoder is the hedge: an AI overlay that's invisible during screen share. It reads the problem on screen and surfaces a working solution in under 2 seconds. Made for the engineer who has done the work but might still blank with a webcam pointed at him. Works on HackerRank, CodeSignal, CoderPad, and Karat.
CME Group interview FAQ
How much time should I spend on trie problems before CME's assessment?+
Trie shows up in half the reported problems here. Build a trie from scratch at least three times without looking at notes. Understand insert, search, and prefix-matching. One or two standard trie problems should cement it. You need muscle memory, not theory.
Is dynamic programming heavily tested at CME?+
It appears once in the available data, paired with array problems. At CME, DP seems focused on state-based decisions (like stock trading) rather than complex recursion. Master the state-transition pattern and you'll handle their DP problems.
Should I worry about harder problems if CME's known questions are all easy?+
No. The reported problems are easy, and that's real signal. Don't waste time grinding hard problems. Nail string/trie and array/DP at the easy to medium level. Clean execution under pressure is what they're measuring.
How do I prepare for the string problem specifically?+
The longest common prefix problem tests both string traversal and trie understanding. Build a trie-based solution and a simple comparison solution. Know when to use each. Practice until you can code it in under 5 minutes.
What's the best order to study these two problem patterns?+
Start with the stock-trading problem. It's easier to visualize and builds confidence fast. Then move to trie construction. Having one pattern locked in before hitting the harder conceptual problem keeps momentum and reduces panic during the actual assessment.