IQVIA interview prep
3 practice questions on the topics candidates reported from IQVIA interviews, with answers. The questions are ours; each one links to the interview report that names its topic.
DSA 1
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How many palindromic numbers are there from 1 to 200?
- 19
- 29
- 27
- 28
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D. 28
9 one-digit numbers, 9 two-digit ones (11 to 99) and 10 three-digit ones up to 200 (101, 111, ..., 191). Rather than testing every number, generate palindromes by mirroring a first half.
This topic is named in a candidate’s interview report: SDE interview, 2020, on Code360.
DBMS and SQL 2
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Students take many courses and each course has many students. How is this stored in a normalised schema?
- A comma-separated list of course ids in the student table
- One column per course in the student table
- A course_id column in student and a student_id column in course
- A third table enrollment(student_id, course_id), each a foreign key, together forming its primary key
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D. A third table enrollment(student_id, course_id), each a foreign key, together forming its primary key
A many-to-many relationship becomes a junction table. Each row records one enrolment, and the composite key stops the same student being enrolled in the same course twice.
This topic is named in a candidate’s interview report: SDE interview, 2020, on Code360.
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Queries like WHERE created_at BETWEEN '2026-01-01' AND '2026-01-31' run often. Which index serves them: a B+ tree or a hash index?
- A B+ tree, because its keys are kept in order and its leaves are linked, so it finds the start of the range and reads forward
- A hash index, because its lookups are O(1)
- Either; they behave the same for ranges
- Neither; a range always scans the whole table
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A. A B+ tree, because its keys are kept in order and its leaves are linked, so it finds the start of the range and reads forward
Hashing scatters neighbouring keys across buckets, so a hash index answers only exact matches. A B+ tree also serves ORDER BY and prefix matches such as LIKE 'abc%', which is why it is the default index in most relational databases.
This topic is named in a candidate’s interview report: Analyst on-campus interview, 2024, on GeeksforGeeks.