7561 - Subtract

[Sliect]

// your answers
type Rang<T extends Number = 0, P extends 1[] = []> =
  P['length'] extends T ?
    P : Rang<T, [1, ...P]>
type Shift<T extends 1[]> = T extends [infer F, ...infer Rest] ? Rest : []
type Subtract<M extends number, S extends number, L extends 1[] = Rang<M>, R extends 1[] = Rang<S>> = 
  L['length'] extends 0
    ? R['length'] extends 0
      ? 0
      : never
    : R['length'] extends 0
      ? L['length']
      : Subtract<M, S, Shift<L>, Shift<R>>