Epic Systems coding interview
questions, leaked.
12 problems reported across recent Epic Systems interviews. Top patterns: string, hash table, backtracking. The list below is what most reported candidates actually saw, plus the honest play if you can't grind all of it.
Epic Systems interviews lean heavily on string manipulation and hash-table problems, with backtracking patterns woven throughout. You're looking at 12 reported problems across the interview loop, 75% of them medium difficulty. String work dominates (7 problems), hash-tables appear in 4, and backtracking shows up across multiple patterns. The good news: no hard problems reported. The reality: medium-difficulty string and backtracking combinations require speed and pattern recognition under pressure. StealthCoder runs invisibly during the live assessment as your safety net if you blank on a backtracking reconstruction or hash-table construction mid-problem.
Top problems at Epic Systems
| # | Problem | Diff | Frequency | Pass % | Patterns |
|---|---|---|---|---|---|
| 01 | Additive Number | MEDIUM | 100.0 | 33% | String · Backtracking |
| 02 | Letter Combinations of a Phone Number | MEDIUM | 98.1 | 64% | Hash Table · String · Backtracking |
| 03 | Self Dividing Numbers | EASY | 89.3 | 80% | Math |
| 04 | Spiral Matrix | MEDIUM | 85.9 | 54% | Array · Matrix · Simulation |
| 05 | Stepping Numbers | MEDIUM | 84.0 | 48% | Math · Backtracking · Breadth-First Search |
| 06 | Valid Parentheses | EASY | 81.8 | 42% | String · Stack |
| 07 | Word Search | MEDIUM | 65.3 | 45% | Array · String · Backtracking |
| 08 | Angle Between Hands of a Clock | MEDIUM | 65.3 | 64% | Math |
| 09 | Two Sum | EASY | 59.5 | 56% | Array · Hash Table |
| 10 | Palindromic Substrings | MEDIUM | 51.3 | 72% | Two Pointers · String · Dynamic Programming |
| 11 | Longest Substring Without Repeating Characters | MEDIUM | 51.3 | 37% | Hash Table · String · Sliding Window |
| 12 | Bulls and Cows | MEDIUM | 51.3 | 51% | Hash Table · String · Counting |
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 Epic Systems OA. The proctor cannot see it. Screen share cannot detect it. Made by a working FAANG engineer who treats the OA the way companies treat hiring: as a game with rules you should know.
Get StealthCoder- string7 · 58%
- hash table4 · 33%
- backtracking4 · 33%
- array3 · 25%
- math3 · 25%
- matrix2 · 17%
- two pointers1 · 8%
- dynamic programming1 · 8%
- simulation1 · 8%
- stack1 · 8%
String problems aren't just parsing, they're string-building with backtracking (Letter Combinations, Additive Number, Word Search). Hash-tables appear either as direct lookups (Two Sum) or as counting mechanisms for constraint satisfaction (Bulls and Cows, Longest Substring Without Repeating Characters). Backtracking dominates across 4 problems, often combined with matrix or string domains. Your immediate focus: master hash-table counting patterns and recursive backtracking structure on strings. The middle-tier prep: simulation (Spiral Matrix), math angle problems, and DFS traversal. The easiest wins are Valid Parentheses and Self Dividing Numbers, both single-pass or direct iteration. Most candidates underestimate the string-backtracking fusion. If you hit a wall during the live OA on Additive Number or Word Search, StealthCoder surfaces a working recursive solution in seconds, invisible to the proctor.
Companies with similar patterns
If you prepped for Epic Systems, these companies recycle ~60% of the same topics.
You've seen the list.
Now make sure you pass Epic Systems.
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 by a working FAANG engineer who treats the OA the way companies treat hiring: as a game with rules you should know. Works on HackerRank, CodeSignal, CoderPad, and Karat.
Epic Systems interview FAQ
How many hash-table problems should I solve before the Epic OA?+
Four hash-table problems appear in the reported list, but they're not standalone: Two Sum is a warm-up, Bulls and Cows requires counting, Longest Substring pairs hash-table with sliding window. Drill at least 6-8 variations covering counting, constraint-checking, and duplicate detection. Hash-table work is foundational for Epic.
Should I study backtracking first or hash-tables?+
Hash-tables first. Four of the 12 problems use hash-tables, and two-sum-style lookups appear as sub-patterns in backtracking solutions. Spend 2-3 days on hash-table mechanics (counting, set membership, mapping), then shift to backtracking recursion on strings. That's the Epic flow.
Are math problems worth drilling for Epic?+
Three math problems appear (Self Dividing Numbers, Stepping Numbers, Angle Between Hands). Two are medium. They're low-volume compared to string and hash-table work, so treat them as secondary. Solve the three reported ones, understand the patterns, then focus time on string-backtracking combinations.
What's the biggest gap most candidates have on Epic's assessment?+
Backtracking on strings with constraint validation (like Word Search or Additive Number). Most candidates can write DFS, but combining it with string validation and pruning trips them up. Practice recursive state-building on strings specifically, not just generic backtracking templates.
Is 75% medium difficulty hard to handle in one interview?+
It's not the raw difficulty, it's the time pressure. Nine medium problems in a loop means you need to recognize patterns fast and code cleanly. Three easy problems buy you confidence points early. Drill the easy ones cold to build momentum, then hit medium patterns with 15-minute time boxes per problem.