type TupleOfLengthInner<N extends string, Tuple extends any[] = []> = `${Tuple['length']}` extends N
  ? Tuple
  : TupleOfLengthInner<N, [...Tuple, 0]>

type TupleOfLength<N extends string, T extends any[] = []> = N extends `${infer First}${infer Rest}`
  ? TupleOfLength<Rest, [...T, ...T, ...T, ...T, ...T, ...T, ...T, ...T, ...T, ...T, ...TupleOfLengthInner<First>]>
  : T;

type MinusOne<T extends number> = TupleOfLength<`${T}`> extends [infer _, ...infer Rest] ? Rest['length'] : never;

import type { Equal, Expect } from '@type-challenges/utils'

type cases = [
  Expect<Equal<MinusOne<1>, 0>>,
  Expect<Equal<MinusOne<55>, 54>>,
  Expect<Equal<MinusOne<3>, 2>>,
  Expect<Equal<MinusOne<100>, 99>>,
  Expect<Equal<MinusOne<1101>, 1100>>,
]