No. 273 · September 25, 2026 · Brutal
Cartesian product
Implement Cartesian<A, B> so it produces one tuple for every pairing of a member from union A with a member from union B.
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Puzzle
Par 5Puzzle
cartesian-product.tsStroke 1 of 5Not run yet
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Checks
3Cartesian<'a' | 'b', 1 | 2>—→ ['a', 1] | ['a', 2] | ['b', 1] | ['b', 2]Cartesian<'x', true | false>—→ ['x', true] | ['x', false]Cartesian<never, 1>—→ never
How a check is judged Exact type equality, not assignability — an intersection is not the same as the flattened object.
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Short game
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Annotated solution
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