Citadel vs ServiceNow Interview Questions
Citadel lists 101 LeetCode interview questions while ServiceNow lists 71. They share 18 problems — 18% of Citadel's bank and 25% of ServiceNow's. Focus on the overlap first, then drill into 83 Citadel-only and 53 ServiceNow-only questions.
Overview
Preparation Strategy
Step 1 — Shared core: Solve the 18 overlapping problems first. These are the highest-yield questions for candidates interviewing at both Citadel and ServiceNow.
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 ServiceNow-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
18 Shared Questions
High-priority problems to practice for both Citadel and ServiceNow.
| Problem | Difficulty |
|---|---|
| Sliding Window Maximum | Hard |
| LFU Cache | Hard |
| LRU Cache | Medium |
| Merge Intervals | Medium |
| Best Time to Buy and Sell Stock | Easy |
| Number of Islands | Medium |
| Group Anagrams | Medium |
| Trapping Rain Water | Hard |
| Best Time to Buy and Sell Stock II | Medium |
| Combination Sum | Medium |
| Letter Combinations of a Phone Number | Medium |
| Median of Two Sorted Arrays | Hard |
| Asteroid Collision | Medium |
| Longest Common Subsequence | Medium |
| Container With Most Water | Medium |
| Pow(x, n) | Medium |
| Rotting Oranges | Medium |
| Simplify Path | Medium |
Unique to Citadel (83)
Problems in Citadel's list that do not appear at ServiceNow.
Unique to ServiceNow (53)
Problems in ServiceNow's list that do not appear at Citadel.
Frequently Asked Questions
How many LeetCode questions do Citadel and ServiceNow share?
Citadel and ServiceNow share 18 LeetCode interview questions. 83 problems appear only in Citadel's list and 53 appear only in ServiceNow's list.
What topics overlap most between Citadel and ServiceNow?
The most common shared topics between Citadel and ServiceNow are Array (12 shared questions), Hash Table (4 shared questions), Dynamic Programming (4 shared questions), String (4 shared questions), Stack (3 shared questions). Mastering these areas prepares you for both companies.
Which company asks harder LeetCode questions: Citadel or ServiceNow?
Citadel has 5 Easy, 60 Medium, and 36 Hard questions. ServiceNow has 7 Easy, 51 Medium, and 13 Hard questions. Citadel has a higher proportion of Hard problems in its interview set.
How should I prepare if interviewing at both Citadel and ServiceNow?
Start with the 18 shared problems since they cover what both companies ask most often. Then add 20 Citadel-specific and 20 ServiceNow-specific questions to round out your prep.