Citadel vs TCS Interview Questions
Citadel lists 101 LeetCode interview questions while TCS lists 228. They share 29 problems — 29% of Citadel's bank and 13% of TCS's. Focus on the overlap first, then drill into 72 Citadel-only and 199 TCS-only questions.
Overview
Preparation Strategy
Step 1 — Shared core: Solve the 29 overlapping problems first. These are the highest-yield questions for candidates interviewing at both Citadel and TCS.
Step 2 — Company-specific depth: Add Citadel-specific problems like Longest Non-decreasing Subarray From Two Arrays, Minimum Knight Moves, Delete and Earn and TCS-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
29 Shared Questions
High-priority problems to practice for both Citadel and TCS.
| Problem | Difficulty |
|---|---|
| Binary Tree Maximum Path Sum | Hard |
| Sliding Window Maximum | Hard |
| LRU Cache | Medium |
| Merge Intervals | Medium |
| Best Time to Buy and Sell Stock | Easy |
| Find the Duplicate Number | Medium |
| Serialize and Deserialize Binary Tree | Hard |
| Number of Islands | Medium |
| Group Anagrams | Medium |
| Permutations | Medium |
| Merge k Sorted Lists | Hard |
| Trapping Rain Water | Hard |
| N-Queens | Hard |
| Regular Expression Matching | Hard |
| Best Time to Buy and Sell Stock II | Medium |
| Fizz Buzz | Easy |
| Climbing Stairs | Easy |
| Letter Combinations of a Phone Number | Medium |
| Median of Two Sorted Arrays | Hard |
| House Robber | Medium |
| 3Sum | Medium |
| Sqrt(x) | Easy |
| Longest Common Subsequence | Medium |
| Container With Most Water | Medium |
| Pow(x, n) | Medium |
| Longest Increasing Subsequence | Medium |
| Rotting Oranges | Medium |
| Koko Eating Bananas | Medium |
| Integer to Roman | Medium |
Unique to Citadel (72)
Problems in Citadel's list that do not appear at TCS.
Unique to TCS (199)
Problems in TCS's list that do not appear at Citadel.
| Problem | Difficulty |
|---|---|
| Friday Purchases I | Medium |
| Two Sum | Easy |
| Longest Palindromic Substring | Medium |
| Palindrome Number | Easy |
| Maximum Subarray | Medium |
| Move Zeroes | Easy |
| Majority Element | Easy |
| Longest Common Prefix | Easy |
| Sort Colors | Medium |
| Valid Anagram | Easy |
| Find the Index of the First Occurrence in a String | Easy |
| Single Number | Easy |
Frequently Asked Questions
How many LeetCode questions do Citadel and TCS share?
Citadel and TCS share 29 LeetCode interview questions. 72 problems appear only in Citadel's list and 199 appear only in TCS's list.
What topics overlap most between Citadel and TCS?
The most common shared topics between Citadel and TCS are Array (17 shared questions), Dynamic Programming (9 shared questions), String (7 shared questions), Binary Search (5 shared questions), Math (5 shared questions). Mastering these areas prepares you for both companies.
Which company asks harder LeetCode questions: Citadel or TCS?
Citadel has 5 Easy, 60 Medium, and 36 Hard questions. TCS has 99 Easy, 108 Medium, and 21 Hard questions. Citadel has a higher proportion of Hard problems in its interview set.
How should I prepare if interviewing at both Citadel and TCS?
Start with the 29 shared problems since they cover what both companies ask most often. Then add 20 Citadel-specific and 20 TCS-specific questions to round out your prep.