Citadel vs Twitter Interview Questions
Citadel lists 101 LeetCode interview questions while Twitter lists 53. They share 12 problems — 12% of Citadel's bank and 23% of Twitter's. Focus on the overlap first, then drill into 89 Citadel-only and 41 Twitter-only questions.
Overview
Preparation Strategy
Step 1 — Shared core: Solve the 12 overlapping problems first. These are the highest-yield questions for candidates interviewing at both Citadel and Twitter.
Step 2 — Company-specific depth: Add Citadel-specific problems like Longest Non-decreasing Subarray From Two Arrays, Binary Tree Maximum Path Sum, Minimum Knight Moves and Twitter-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
12 Shared Questions
High-priority problems to practice for both Citadel and Twitter.
| Problem | Difficulty |
|---|---|
| LRU Cache | Medium |
| Merge Intervals | Medium |
| Insert Delete GetRandom O(1) | Medium |
| Merge k Sorted Lists | Hard |
| Trapping Rain Water | Hard |
| Regular Expression Matching | Hard |
| Implement Trie (Prefix Tree) | Medium |
| Alien Dictionary | Hard |
| Max Points on a Line | Hard |
| Rotting Oranges | Medium |
| The Skyline Problem | Hard |
| Integer to Roman | Medium |
Unique to Citadel (89)
Problems in Citadel's list that do not appear at Twitter.
Unique to Twitter (41)
Problems in Twitter's list that do not appear at Citadel.
| Problem | Difficulty |
|---|---|
| Valid Parentheses | Easy |
| Multiply Strings | Medium |
| Wildcard Matching | Hard |
| Permutation Sequence | Hard |
| Pascal's Triangle | Easy |
| Word Break II | Hard |
| Time Needed to Buy Tickets | Easy |
| One Edit Distance | Medium |
| Happy Number | Easy |
| Reverse Linked List | Easy |
| Lowest Common Ancestor of a Binary Search Tree | Medium |
| Flatten 2D Vector | Medium |
Frequently Asked Questions
How many LeetCode questions do Citadel and Twitter share?
Citadel and Twitter share 12 LeetCode interview questions. 89 problems appear only in Citadel's list and 41 appear only in Twitter's list.
What topics overlap most between Citadel and Twitter?
The most common shared topics between Citadel and Twitter are Array (7 shared questions), Hash Table (5 shared questions), String (4 shared questions), Design (3 shared questions), Math (3 shared questions). Mastering these areas prepares you for both companies.
Which company asks harder LeetCode questions: Citadel or Twitter?
Citadel has 5 Easy, 60 Medium, and 36 Hard questions. Twitter has 8 Easy, 33 Medium, and 12 Hard questions. Citadel has a higher proportion of Hard problems in its interview set.
How should I prepare if interviewing at both Citadel and Twitter?
Start with the 12 shared problems since they cover what both companies ask most often. Then add 20 Citadel-specific and 20 Twitter-specific questions to round out your prep.