Capital One coding interview
questions, leaked.
47 problems reported across recent Capital One interviews. Top patterns: array, string, math. The list below is what most reported candidates actually saw, plus the honest play if you can't grind all of it.
Capital One's interview has 47 problems in rotation, split 19% easy, 60% medium, 21% hard. You're walking into a gauntlet that's array-heavy (34 of 47 problems touch arrays) with a secondary emphasis on strings and math. The medium band is thick, which means you won't coast. If you blank mid-assessment on a pattern you thought you knew, StealthCoder runs invisibly and surfaces a solution in seconds. Most candidates don't have that hedge.
Top problems at Capital One
| # | Problem | Diff | Frequency | Pass % | Patterns |
|---|---|---|---|---|---|
| 01 | Simple Bank System | MEDIUM | 100.0 | 61% | Array · Hash Table · Design |
| 02 | Spiral Matrix | MEDIUM | 92.8 | 54% | Array · Matrix · Simulation |
| 03 | Block Placement Queries | HARD | 92.0 | 17% | Array · Binary Search · Binary Indexed Tree |
| 04 | Text Justification | HARD | 82.9 | 48% | Array · String · Simulation |
| 05 | Minimum Operations to Write the Letter Y on a Grid | MEDIUM | 81.6 | 62% | Array · Hash Table · Matrix |
| 06 | Candy Crush | MEDIUM | 75.3 | 77% | Array · Two Pointers · Matrix |
| 07 | Count Alternating Subarrays | MEDIUM | 75.3 | 56% | Array · Math |
| 08 | Rotate Image | MEDIUM | 73.4 | 78% | Array · Math · Matrix |
| 09 | Four Divisors | MEDIUM | 73.4 | 45% | Array · Math |
| 10 | Simplify Path | MEDIUM | 71.2 | 48% | String · Stack |
| 11 | Count Operations to Obtain Zero | EASY | 71.2 | 75% | Math · Simulation |
| 12 | Longest Continuous Subarray With Absolute Diff Less Than or Equal to Limit | MEDIUM | 68.9 | 57% | Array · Queue · Sliding Window |
| 13 | Split Message Based on Limit | HARD | 68.9 | 43% | String · Binary Search · Enumeration |
| 14 | Rotating the Box | MEDIUM | 66.1 | 79% | Array · Two Pointers · Matrix |
| 15 | Number of Black Blocks | MEDIUM | 63.0 | 39% | Array · Hash Table · Enumeration |
| 16 | Count Prefix and Suffix Pairs II | HARD | 59.3 | 27% | Array · String · Trie |
| 17 | Largest Rectangle in Histogram | HARD | 59.3 | 47% | Array · Stack · Monotonic Stack |
| 18 | Best Time to Buy and Sell Stock | EASY | 59.3 | 55% | Array · Dynamic Programming |
| 19 | Remove Boxes | HARD | 59.3 | 48% | Array · Dynamic Programming · Memoization |
| 20 | Find the Length of the Longest Common Prefix | MEDIUM | 59.3 | 56% | Array · Hash Table · String |
| 21 | Number of Flowers in Full Bloom | HARD | 59.3 | 57% | Array · Hash Table · Binary Search |
| 22 | Number of Subarrays That Match a Pattern I | MEDIUM | 54.8 | 67% | Array · Rolling Hash · String Matching |
| 23 | Palindrome Number | EASY | 54.8 | 59% | Math |
| 24 | Word Search | MEDIUM | 54.8 | 45% | Array · String · Backtracking |
| 25 | Coin Change | MEDIUM | 54.8 | 46% | Array · Dynamic Programming · Breadth-First Search |
| 26 | Design File System | MEDIUM | 54.8 | 64% | Hash Table · String · Design |
| 27 | Merge Intervals | MEDIUM | 49.0 | 49% | Array · Sorting |
| 28 | Add Strings | EASY | 49.0 | 52% | Math · String · Simulation |
| 29 | Non-overlapping Intervals | MEDIUM | 49.0 | 56% | Array · Dynamic Programming · Greedy |
| 30 | Number of Islands | MEDIUM | 49.0 | 62% | Array · Depth-First Search · Breadth-First Search |
| 31 | Word Search II | HARD | 49.0 | 37% | Array · String · Backtracking |
| 32 | Add Two Numbers | MEDIUM | 49.0 | 46% | Linked List · Math · Recursion |
| 33 | Binary Tree Paths | EASY | 49.0 | 67% | String · Backtracking · Tree |
| 34 | Number of Adjacent Elements With the Same Color | MEDIUM | 40.8 | 56% | Array |
| 35 | LRU Cache | MEDIUM | 40.8 | 45% | Hash Table · Linked List · Design |
| 36 | Merge Two Sorted Lists | EASY | 40.8 | 67% | Linked List · Recursion |
| 37 | K-diff Pairs in an Array | MEDIUM | 40.8 | 45% | Array · Hash Table · Two Pointers |
| 38 | Meeting Rooms II | MEDIUM | 40.8 | 52% | Array · Two Pointers · Greedy |
| 39 | Rotate Array | MEDIUM | 40.8 | 43% | Array · Math · Two Pointers |
| 40 | Roman to Integer | EASY | 40.8 | 65% | Hash Table · Math · String |
| 41 | Valid Parentheses | EASY | 40.8 | 42% | String · Stack |
| 42 | Find Servers That Handled Most Number of Requests | HARD | 40.8 | 44% | Array · Greedy · Heap (Priority Queue) |
| 43 | Get Biggest Three Rhombus Sums in a Grid | MEDIUM | 40.8 | 49% | Array · Math · Sorting |
| 44 | Reverse Nodes in k-Group | HARD | 40.8 | 63% | Linked List · Recursion |
| 45 | Best Time to Buy and Sell Stock II | MEDIUM | 40.8 | 70% | Array · Dynamic Programming · Greedy |
| 46 | Minimum Absolute Difference Between Elements With Constraint | MEDIUM | 40.8 | 34% | Array · Binary Search · Ordered Set |
| 47 | Count Prefix and Suffix Pairs I | EASY | 40.8 | 78% | Array · String · Trie |
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 Capital One 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- array34 · 72%
- string13 · 28%
- math10 · 21%
- matrix9 · 19%
- hash table9 · 19%
- sorting6 · 13%
- simulation6 · 13%
- two pointers5 · 11%
- binary search5 · 11%
- trie5 · 11%
Arrays dominate Capital One's question pool by a landslide. You'll see them combined with matrices, hashing, and simulation logic. String work is present but lighter (13 problems). Math and matrix problems often layer in search or geometry, so two-pointers and binary search are force multipliers, not afterthoughts. Simulation patterns show up repeatedly (think Spiral Matrix, Candy Crush, Rotating the Box), so get comfortable translating problem prose into step-by-step coordinate logic. The hard tier jumps to segment trees and binary indexed trees, but most of your reps should be medium: that's where volume is, and where small gaps in pattern recognition hurt. If a tree-based or complex-simulation question lands live and you hesitate, StealthCoder is your real-time backup to keep pace.
Companies with similar patterns
If you prepped for Capital One, these companies recycle ~60% of the same topics.
You've seen the list.
Now make sure you pass Capital One.
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.
Capital One interview FAQ
How many array problems should I drill before the Capital One OA?+
Arrays appear in 72% of Capital One's question bank. Drill at least 20 to 25 array problems, mixing solo arrays, arrays as grids, and arrays with hash tables. Hit Spiral Matrix, Rotate Image, and the block/placement problems. You can't skip this.
Is simulation a real weak point for Capital One, or is it overstated?+
Simulation appears in 6 of 47 problems, but it often pairs with arrays or matrices. Text Justification, Candy Crush, and Rotating the Box all require you to translate logic into indexing and state changes. If you nail arrays, simulation becomes a confidence boost, not a trap.
Should I study dynamic programming before my Capital One interview?+
DP shows up in only 5 problems (11% of the pool). It's a lower-priority topic for Capital One. Focus on arrays, strings, and math first. DP is a nice-to-have if you've cleared the core patterns with time left.
How much time should I spend on hard problems versus mediums?+
Mediums are 60% of the pool. Spend 70% of your prep time there. Hard problems (21%) often use segment trees or binary indexed trees, which are rare. Master mediums first, then tackle hard problems if you're confident on arrays and simulation.
What's the right order to study: arrays, strings, then math?+
Yes. Arrays are 72% of Capital One's problems, so drill those first (15 to 20 problems minimum). Strings are 28% of the pool, often paired with arrays or stacks (Simplify Path). Math appears solo (Four Divisors, Count Alternating Subarrays) and in matrices. Array mastery unlocks the rest.