function buildStaircase(n: number): number[][] {
  const result: number[][] = []
  let lastNumber: number = 1

  for (let i = 0; i < n; i++) {
    const numberOfItems = i + 1

    result.push(
      Array.from({ length: numberOfItems })
      .map((_, index) => lastNumber + index)
    )

    lastNumber += numberOfItems
  }

  return result
}

// No modificar: necesario para evaluar el resultado.
export { buildStaircase };