EPAM Systems coding interview
questions, leaked.
43 problems reported across recent EPAM Systems interviews. Top patterns: array, hash table, string. The list below is what most reported candidates actually saw, plus the honest play if you can't grind all of it.
EPAM Systems pulls from a solid fundamentals mix: 43 problems across 7 difficulty bands, heavily weighted toward arrays (21 appearances) and hash tables (11). You're looking at mostly medium problems (24 of 43), with just 2 hard outliers. The real story is arrays and strings dominate the interview, but hash-table and two-pointer patterns show up constantly. If you've drilled Two Sum and Longest Substring Without Repeating Characters, you're halfway there. If you blank mid-assessment, StealthCoder runs invisible to the proctor and surfaces a working solution in seconds.
Top problems at EPAM Systems
| # | Problem | Diff | Frequency | Pass % | Patterns |
|---|---|---|---|---|---|
| 01 | Longest Substring Without Repeating Characters | MEDIUM | 100.0 | 37% | Hash Table · String · Sliding Window |
| 02 | Valid Parentheses | EASY | 100.0 | 42% | String · Stack |
| 03 | Two Sum | EASY | 97.6 | 56% | Array · Hash Table |
| 04 | Group Anagrams | MEDIUM | 97.6 | 71% | Array · Hash Table · String |
| 05 | Minimum Operations to Make a Uni-Value Grid | MEDIUM | 97.6 | 67% | Array · Math · Sorting |
| 06 | Longest Palindromic Substring | MEDIUM | 91.8 | 36% | Two Pointers · String · Dynamic Programming |
| 07 | Longest Common Prefix | EASY | 84.5 | 45% | String · Trie |
| 08 | Valid Anagram | EASY | 84.5 | 67% | Hash Table · String · Sorting |
| 09 | Valid Palindrome | EASY | 79.8 | 51% | Two Pointers · String |
| 10 | Merge Sorted Array | EASY | 79.8 | 53% | Array · Two Pointers · Sorting |
| 11 | Best Time to Buy and Sell Stock | EASY | 74.1 | 55% | Array · Dynamic Programming |
| 12 | Trapping Rain Water | HARD | 66.8 | 65% | Array · Two Pointers · Dynamic Programming |
| 13 | Maximum Difference Between Node and Ancestor | MEDIUM | 66.8 | 78% | Tree · Depth-First Search · Binary Tree |
| 14 | Pow(x, n) | MEDIUM | 66.8 | 37% | Math · Recursion |
| 15 | Reverse String | EASY | 66.8 | 80% | Two Pointers · String |
| 16 | Two Sum II - Input Array Is Sorted | MEDIUM | 66.8 | 63% | Array · Two Pointers · Binary Search |
| 17 | Palindrome Number | EASY | 66.8 | 59% | Math |
| 18 | Merge Two Sorted Lists | EASY | 66.8 | 67% | Linked List · Recursion |
| 19 | 3Sum | MEDIUM | 66.8 | 37% | Array · Two Pointers · Sorting |
| 20 | Duplicate Emails | EASY | 56.5 | 72% | Database |
| 21 | Partition Equal Subset Sum | MEDIUM | 56.5 | 48% | Array · Dynamic Programming |
| 22 | Managers with at Least 5 Direct Reports | MEDIUM | 56.5 | 49% | Database |
| 23 | Kth Largest Element in an Array | MEDIUM | 56.5 | 68% | Array · Divide and Conquer · Sorting |
| 24 | Reverse Integer | MEDIUM | 56.5 | 30% | Math |
| 25 | Longest Consecutive Sequence | MEDIUM | 56.5 | 47% | Array · Hash Table · Union Find |
| 26 | String Compression | MEDIUM | 56.5 | 58% | Two Pointers · String |
| 27 | House Robber | MEDIUM | 56.5 | 52% | Array · Dynamic Programming |
| 28 | Coin Change | MEDIUM | 56.5 | 46% | Array · Dynamic Programming · Breadth-First Search |
| 29 | Binary Search | EASY | 56.5 | 60% | Array · Binary Search |
| 30 | To Be Or Not To Be | EASY | 56.5 | 63% | |
| 31 | Asteroid Collision | MEDIUM | 56.5 | 46% | Array · Stack · Simulation |
| 32 | Add Two Numbers | MEDIUM | 56.5 | 46% | Linked List · Math · Recursion |
| 33 | Ugly Number II | MEDIUM | 56.5 | 49% | Hash Table · Math · Dynamic Programming |
| 34 | Isomorphic Strings | EASY | 56.5 | 47% | Hash Table · String |
| 35 | Linked List Cycle | EASY | 56.5 | 53% | Hash Table · Linked List · Two Pointers |
| 36 | Reverse Linked List II | MEDIUM | 56.5 | 50% | Linked List |
| 37 | Rotate Array | MEDIUM | 56.5 | 43% | Array · Math · Two Pointers |
| 38 | First Missing Positive | HARD | 56.5 | 41% | Array · Hash Table |
| 39 | Top K Frequent Elements | MEDIUM | 56.5 | 65% | Array · Hash Table · Divide and Conquer |
| 40 | First Unique Character in a String | EASY | 56.5 | 64% | Hash Table · String · Queue |
| 41 | Running Sum of 1d Array | EASY | 56.5 | 87% | Array · Prefix Sum |
| 42 | Merge Intervals | MEDIUM | 56.5 | 49% | Array · Sorting |
| 43 | Search in Rotated Sorted Array | MEDIUM | 56.5 | 43% | Array · Binary Search |
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 EPAM Systems OA. The proctor cannot see it. Screen share cannot detect it. Built by an engineer who got tired of watching his cohort grind for six months and still get filtered at the OA stage.
Get StealthCoder- array21 · 49%
- hash table11 · 26%
- string11 · 26%
- two pointers10 · 23%
- sorting8 · 19%
- dynamic programming7 · 16%
- math7 · 16%
- linked list4 · 9%
- stack3 · 7%
- heap priority queue3 · 7%
The distribution tells you where to spend your week. Arrays are the backbone of EPAM's assessment: 21 problems mean you'll see at least one array pattern per question. Hash tables (11 problems) pair directly with strings (11 problems) in classics like Group Anagrams and Valid Anagram. Two-pointers show up 10 times, often layered with strings or arrays (Merge Sorted Array, Valid Palindrome). Dynamic programming is optional depth, not required. The hard problems (Trapping Rain Water) are rare, so nail the mediums first. Most problems cluster around string manipulation, sorting, and hash-based lookups. Hit arrays, hash tables, and two-pointers hard. Strings come naturally if you solve the first two. For gaps in your muscle memory, StealthCoder is your hedge during the live assessment.
Companies with similar patterns
If you prepped for EPAM Systems, these companies recycle ~60% of the same topics.
You've seen the list.
Now make sure you pass EPAM 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. Built by an engineer who got tired of watching his cohort grind for six months and still get filtered at the OA stage. Works on HackerRank, CodeSignal, CoderPad, and Karat.
EPAM Systems interview FAQ
How many array problems should I solve to be ready for EPAM?+
Array problems represent half the EPAM question pool (21 of 43). Solve at least 12 to 15 array problems before your assessment, focusing on classics like Two Sum, Merge Sorted Array, and Best Time to Buy and Sell Stock. These three alone map to patterns you'll see repeatedly.
Is dynamic programming required for EPAM?+
No. Only 7 of 43 problems involve DP, and most appear as secondary patterns (like Longest Substring Without Repeating Characters uses sliding window first). Master arrays, hash tables, and two-pointers first. DP is a bonus if you have time.
Should I study hash tables before two-pointers?+
Study them in parallel. Hash tables appear in 11 problems, two-pointers in 10. Many overlap (Group Anagrams, Valid Anagram). Spend 2 to 3 days drilling both simultaneously. They're complementary, not sequential.
What's the hardest topic I'll see on EPAM?+
Only 2 of 43 problems are hard difficulty. Trapping Rain Water is the notorious one, requiring dynamic programming, two-pointers, or a monotonic stack. If you see it and panic, you know it's a rarity. Skip it and solve the 24 medium problems first.
Are string problems standalone or mixed with arrays and hash tables?+
Always mixed. Longest Substring Without Repeating Characters uses hash tables and sliding window. Group Anagrams uses sorting and hash tables. Valid Anagram uses hash tables. Treat strings as the surface and hash tables or sorting as the tool. You can't master one without the other.