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Match countries in a pairwise format

General/Othermedium0.3 min readPremium
Frequency
Low
Asked at 1 company
Category
243
questions in General/Other
Difficulty Split
151E|43M|49H
in this category
Total Bank
1,863
across 7 categories
Asked at these companies
KPMG
Key Concepts Tested
joinpartitionpythonsql
Expert AnswerPremium
57 wordsInterview-ready
Produce unique pairs (A,B) with A<B. SQL: SELECT a.country c1, b.country c2 FROM countries a CROSS JOIN countries b WHERE a.country < b.country. Python: list(combinations(countries, 2)). Output: N*(N-1)/2 pairs. SCALABILITY: CROSS JOIN is O(n²)—avoid for large n; use sampling or pre-aggregation....
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