These are Data Structures questions of the kind Infosys actually asks — the patterns that keep coming back in Infosys'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.
Infosys Data Structures concept questions
Why do compilers convert infix expressions (2 + 3 * 4) to postfix (2 3 4 * +) before evaluating? And which data structure powers both the conversion and the evaluation?
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Infosys Data Structures applied & hands-on questions
Evaluate the postfix expression "5 1 2 + 4 * + 3 -" with a stack, showing the stack after every token.
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Is 1 → 2 → 3 → 2 → 1 a palindrome? Do it in O(n) time and O(1) space — which forces you to combine two lesson techniques.
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How to use this page: Infosys 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 Infosys Data Structures rounds test — and the Infosys exam guide covers the rest of their selection process.