Citadel vs PayPal Interview Questions
Citadel lists 101 LeetCode interview questions while PayPal lists 105. They share 30 problems — 30% of Citadel's bank and 29% of PayPal's. Focus on the overlap first, then drill into 71 Citadel-only and 75 PayPal-only questions.
Overview
Preparation Strategy
Step 1 — Shared core: Solve the 30 overlapping problems first. These are the highest-yield questions for candidates interviewing at both Citadel and PayPal.
Step 2 — Company-specific depth: Add Citadel-specific problems like Longest Non-decreasing Subarray From Two Arrays, Minimum Knight Moves, Delete and Earn and PayPal-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
30 Shared Questions
High-priority problems to practice for both Citadel and PayPal.
| Problem | Difficulty |
|---|---|
| Binary Tree Maximum Path Sum | Hard |
| Palindromic Substrings | Medium |
| LFU Cache | Hard |
| LRU Cache | Medium |
| Merge Intervals | Medium |
| Longest String Chain | Medium |
| Best Time to Buy and Sell Stock | Easy |
| Serialize and Deserialize Binary Tree | Hard |
| Number of Islands | Medium |
| Meeting Scheduler | Medium |
| Find Median from Data Stream | Hard |
| Group Anagrams | Medium |
| Search Suggestions System | Medium |
| Trapping Rain Water | Hard |
| Fizz Buzz | Easy |
| Combination Sum | Medium |
| Best Time to Buy and Sell Stock III | Hard |
| Climbing Stairs | Easy |
| Median of Two Sorted Arrays | Hard |
| Maximal Square | Medium |
| House Robber | Medium |
| 3Sum | Medium |
| Word Search | Medium |
| Asteroid Collision | Medium |
| Search a 2D Matrix II | Medium |
| Container With Most Water | Medium |
| Longest Increasing Subsequence | Medium |
| Rotting Oranges | Medium |
| Course Schedule | Medium |
| Koko Eating Bananas | Medium |
Unique to Citadel (71)
Problems in Citadel's list that do not appear at PayPal.
Unique to PayPal (75)
Problems in PayPal's list that do not appear at Citadel.
Frequently Asked Questions
How many LeetCode questions do Citadel and PayPal share?
Citadel and PayPal share 30 LeetCode interview questions. 71 problems appear only in Citadel's list and 75 appear only in PayPal's list.
What topics overlap most between Citadel and PayPal?
The most common shared topics between Citadel and PayPal are Array (21 shared questions), Dynamic Programming (10 shared questions), Two Pointers (7 shared questions), String (7 shared questions), Sorting (7 shared questions). Mastering these areas prepares you for both companies.
Which company asks harder LeetCode questions: Citadel or PayPal?
Citadel has 5 Easy, 60 Medium, and 36 Hard questions. PayPal has 19 Easy, 69 Medium, and 17 Hard questions. Citadel has a higher proportion of Hard problems in its interview set.
How should I prepare if interviewing at both Citadel and PayPal?
Start with the 30 shared problems since they cover what both companies ask most often. Then add 20 Citadel-specific and 20 PayPal-specific questions to round out your prep.