function maxMin(k: number, arr: number[]): number {
  let smallest = Number.POSITIVE_INFINITY;
  const sorted = arr.sort((a,b) => a-b);
  
  for (let i=0; i <= sorted.length - k; i++) {
    smallest = Math.min(smallest, sorted[i + k - 1] - sorted[i]);
  }
  
  return smallest;
}