export function countPairsWithDiffK(numbers: number[], k: number): number {
  const pairs = [];
  for (let i = 0; i < numbers.length - 1; i++) {
    for (let j = i + 1; j < numbers.length; j++) {
      const op = Math.abs(numbers[i] - numbers[j]);
      if (op !== k) continue;
      const minValue = (numbers[i] < numbers[j]) ? numbers[i] : numbers[j];
      const maxValue = (numbers[i] > numbers[j]) ? numbers[i] : numbers[j];
      const value = `${minValue},${maxValue}`;
      if (!pairs.includes(value)) pairs.push(value);
    }
  }
  return pairs.length;
}