function max(numbers: number[]): number{
  return numbers.reduce((prev,cur)=> cur>prev ? cur : prev,0)
}

function groupByRange(numbers: number[], rangeSize: number): Record<string, number[]> {
  // Escribe tu solución aquí
  if(numbers.length === 0) return {}
  return Array.from({length:max(numbers)+rangeSize})
              .map((_,index) => index + 1)
              .filter(n => n % rangeSize === 0)
              .reduce((acc,cur) => {
                const numerosDentroDelRango = numbers.filter(n => n >= cur-rangeSize && n < cur);
                if(numerosDentroDelRango.length>0){ 
                  acc[`${cur-rangeSize}-${cur}`] = numbers.filter(n => n >= cur-rangeSize && n < cur)
                }
                return acc;
              },{})
}

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