46. implement Subtract<A, B>

TypeScript

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Similar to 38. implement Add<A, B>, please implement Subtract<A, B>.

  1. only need to consider positive integers
  2. B is guaranteed to be smaller or equal to A
type A = Subtract<1, 1> // 0
type B = Subtract<10, 3> // 7
type C = Subtract<3, 10> // never

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