MongoDB Coding Interview Questions
We track 21 coding questions asked at MongoDB, tagged with the algorithms and concepts they test. The most common: Hash Table, Array, String, Design, Binary Search.
Browse all 21 MongoDB questions →Concept mix
Each question's weight is split evenly across its concepts, so the shares sum to 100%.
- Array15.5%
- Hash Table10.9%
- String9.1%
- Design6.7%
- Binary Search6.7%
- Depth-First Search6.0%
- Breadth-First Search4.2%
- Two Pointers3.9%
- Heap (Priority Queue)3.6%
- Binary Tree3.2%
- Other (18)30.2%
How many questions involve each concept
Share of all 21 tracked MongoDB questions that touch each concept. Questions usually involve several, so these overlap.
- Hash Table42.9%
- Array38.1%
- String28.6%
- Design23.8%
- Binary Search19.0%
- Depth-First Search19.0%
- Breadth-First Search14.3%
- Heap (Priority Queue)14.3%
- Trie14.3%
- Binary Tree9.5%
- Dynamic Programming9.5%
- Graph Theory9.5%
Where MongoDB differs from the average company
Concept weight at MongoDB relative to the average across all companies we track. Green means MongoDB leans on it harder than most.
- Trie6.2×
- Memoization5.7×
- Design5.2×
- Graph Theory2.8×
- Array0.80×
- Dynamic Programming0.27×
MongoDB specialties
Concepts that show up at MongoDB but are rarely asked elsewhere. They are easy to get blindsided by.
Difficulty mix
Level split of the 21 tracked MongoDB questions.
- Junior10% (2)
- Mid/Senior67% (14)
- Staff24% (5)
Every concept in MongoDB interviews
| Concept | Questions | % of questions | Share of mix |
|---|---|---|---|
| Hash Table | 9 | 42.9% | 10.9% |
| Array | 8 | 38.1% | 15.5% |
| String | 6 | 28.6% | 9.1% |
| Design | 5 | 23.8% | 6.7% |
| Binary Search | 4 | 19.0% | 6.7% |
| Depth-First Search | 4 | 19.0% | 6.0% |
| Breadth-First Search | 3 | 14.3% | 4.2% |
| Heap (Priority Queue) | 3 | 14.3% | 3.6% |
| Trie | 3 | 14.3% | 3.1% |
| Binary Tree | 2 | 9.5% | 3.2% |
| Dynamic Programming | 2 | 9.5% | 1.7% |
| Graph Theory | 2 | 9.5% | 2.8% |
| Linked List | 2 | 9.5% | 2.8% |
| Memoization | 2 | 9.5% | 1.7% |
| Tree | 2 | 9.5% | 3.2% |
| Two Pointers | 2 | 9.5% | 3.9% |
| Backtracking | 1 | 4.8% | 0.8% |
| Data Stream | 1 | 4.8% | 1.1% |
| Divide and Conquer | 1 | 4.8% | 1.4% |
| Doubly-Linked List | 1 | 4.8% | 1.4% |
| Merge Sort | 1 | 4.8% | 1.4% |
| Monotonic Queue | 1 | 4.8% | 1.1% |
| Ordered Set | 1 | 4.8% | 1.1% |
| Queue | 1 | 4.8% | 1.1% |
| Simulation | 1 | 4.8% | 1.9% |
| Sliding Window | 1 | 4.8% | 1.1% |
| Sorting | 1 | 4.8% | 1.1% |
| Topological Sort | 1 | 4.8% | 1.4% |
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