These are Data Structures questions of the kind TCS actually asks — the patterns that keep coming back in TCS's AI project interviews, where what matters is applying Data Structures sensibly for clients rather than research depth. Treat this page as a mock interview: say every answer out loud before revealing it. If one surprises you, the lesson behind it is linked at the bottom.
TCS Data Structures concept questions
A college stores marks of 120 students, accessed constantly by roll number (1–120), with marks occasionally updated. Which data structure, and why not a hash map or linked list?
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What is a circular queue, what problem does it solve over a simple array queue, and where is it used in real systems?
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TCS Data Structures applied & hands-on questions
Given sorted [1, 1, 2, 3, 3, 3, 5], move the unique values to the front in place and return their count. O(n) time, O(1) space.
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How to use this page: TCS rarely asks something you've never seen — they ask a standard Data Structures concept and then push one level deeper ("why?", "what would you do if..."). Master the concept in the Data Structures course lessons, and the follow-up stops being scary.
Keep practising: Hash Tables, Linked Lists, Heaps and Choosing the Right Structure cover what most TCS Data Structures rounds test — and the TCS NQT exam guide covers the rest of their selection process.