IBM vs MongoDB Interview Questions
IBM lists 115 LeetCode interview questions while MongoDB lists 24. They share 5 problems — 4% of IBM's bank and 21% of MongoDB's. Focus on the overlap first, then drill into 110 IBM-only and 19 MongoDB-only questions.
Overview
Preparation Strategy
Step 1 — Shared core: Solve the 5 overlapping problems first. These are the highest-yield questions for candidates interviewing at both IBM and MongoDB.
Step 2 — Company-specific depth: Add IBM-specific problems like Find the Smallest Divisor Given a Threshold, Gray Code, 3Sum and MongoDB-specific problems from the exclusive lists below.
Step 3 — Difficulty tuning: MongoDB skews harder in our data. Budget extra time for Hard problems if you are targeting that company.
Difficulty Comparison
Top Shared Topics
5 Shared Questions
High-priority problems to practice for both IBM and MongoDB.
| Problem | Difficulty |
|---|---|
| Merge Intervals | Medium |
| String Compression | Medium |
| Intersection of Two Arrays | Easy |
| Word Break | Medium |
| LRU Cache | Medium |
Unique to IBM (110)
Problems in IBM's list that do not appear at MongoDB.
| Problem | Difficulty |
|---|---|
| Find the Smallest Divisor Given a Threshold | Medium |
| Gray Code | Medium |
| 3Sum | Medium |
| Exclusive Time of Functions | Medium |
| Integer to Roman | Medium |
| Minimum Operations to Make Columns Strictly Increasing | Easy |
| Fizz Buzz | Easy |
| Roman to Integer | Easy |
| Best Time to Buy and Sell Stock | Easy |
| Count Ways to Group Overlapping Ranges | Medium |
| Two Sum | Easy |
| Meeting Rooms II | Medium |
Unique to MongoDB (19)
Problems in MongoDB's list that do not appear at IBM.
| Problem | Difficulty |
|---|---|
| Implement Trie (Prefix Tree) | Medium |
| Snapshot Array | Medium |
| Text Justification | Hard |
| Merge k Sorted Lists | Hard |
| Convert JSON String to Object | Hard |
| Insert Interval | Medium |
| Web Crawler Multithreaded | Medium |
| Stock Price Fluctuation | Medium |
| Course Schedule II | Medium |
| Merge Two Binary Trees | Easy |
| Sliding Window Maximum | Hard |
| Lowest Common Ancestor of a Binary Tree | Medium |
Frequently Asked Questions
How many LeetCode questions do IBM and MongoDB share?
IBM and MongoDB share 5 LeetCode interview questions. 110 problems appear only in IBM's list and 19 appear only in MongoDB's list.
What topics overlap most between IBM and MongoDB?
The most common shared topics between IBM and MongoDB are Array (3 shared questions), Hash Table (3 shared questions), Sorting (2 shared questions), Two Pointers (2 shared questions), String (2 shared questions). Mastering these areas prepares you for both companies.
Which company asks harder LeetCode questions: IBM or MongoDB?
IBM has 33 Easy, 73 Medium, and 9 Hard questions. MongoDB has 3 Easy, 15 Medium, and 6 Hard questions. MongoDB has a higher proportion of Hard problems in its interview set.
How should I prepare if interviewing at both IBM and MongoDB?
Start with the 5 shared problems since they cover what both companies ask most often. Then add 20 IBM-specific and 19 MongoDB-specific questions to round out your prep.