Citadel vs DoorDash Interview Questions
Citadel lists 101 LeetCode interview questions while DoorDash lists 78. They share 22 problems — 22% of Citadel's bank and 28% of DoorDash's. Focus on the overlap first, then drill into 79 Citadel-only and 56 DoorDash-only questions.
Overview
Preparation Strategy
Step 1 — Shared core: Solve the 22 overlapping problems first. These are the highest-yield questions for candidates interviewing at both Citadel and DoorDash.
Step 2 — Company-specific depth: Add Citadel-specific problems like Longest Non-decreasing Subarray From Two Arrays, Minimum Knight Moves, Delete and Earn and DoorDash-specific problems from the exclusive lists below.
Step 3 — Difficulty tuning: Citadel skews harder in our data. Budget extra time for Hard problems if you are targeting that company.
Difficulty Comparison
Top Shared Topics
22 Shared Questions
High-priority problems to practice for both Citadel and DoorDash.
| Problem | Difficulty |
|---|---|
| Binary Tree Maximum Path Sum | Hard |
| Sliding Window Maximum | Hard |
| LFU Cache | Hard |
| LRU Cache | Medium |
| Merge Intervals | Medium |
| Serialize and Deserialize Binary Tree | Hard |
| Insert Delete GetRandom O(1) | Medium |
| Number of Islands | Medium |
| Sudoku Solver | Hard |
| Group Anagrams | Medium |
| Merge k Sorted Lists | Hard |
| Search Suggestions System | Medium |
| Implement Trie (Prefix Tree) | Medium |
| Longest Increasing Path in a Matrix | Hard |
| Asteroid Collision | Medium |
| Longest Common Subsequence | Medium |
| Rotting Oranges | Medium |
| Basic Calculator | Hard |
| Course Schedule II | Medium |
| Course Schedule | Medium |
| Koko Eating Bananas | Medium |
| Integer to Roman | Medium |
Unique to Citadel (79)
Problems in Citadel's list that do not appear at DoorDash.
Unique to DoorDash (56)
Problems in DoorDash's list that do not appear at Citadel.
Frequently Asked Questions
How many LeetCode questions do Citadel and DoorDash share?
Citadel and DoorDash share 22 LeetCode interview questions. 79 problems appear only in Citadel's list and 56 appear only in DoorDash's list.
What topics overlap most between Citadel and DoorDash?
The most common shared topics between Citadel and DoorDash are Array (11 shared questions), Hash Table (7 shared questions), String (7 shared questions), Depth-First Search (6 shared questions), Breadth-First Search (6 shared questions). Mastering these areas prepares you for both companies.
Which company asks harder LeetCode questions: Citadel or DoorDash?
Citadel has 5 Easy, 60 Medium, and 36 Hard questions. DoorDash has 7 Easy, 45 Medium, and 26 Hard questions. Citadel has a higher proportion of Hard problems in its interview set.
How should I prepare if interviewing at both Citadel and DoorDash?
Start with the 22 shared problems since they cover what both companies ask most often. Then add 20 Citadel-specific and 20 DoorDash-specific questions to round out your prep.