function closestNumbers(arr) {
  const sortedArray = [...arr].sort((a, b) => a - b);
  const startingPoint = sortedArray.splice(0, 2);

  return sortedArray.reduce((acc, element, index) => {
    const previosElement = index === 0 ? acc[1] : sortedArray[index - 1];
    const currentDifference = Math.abs(element - previosElement);
    const existingDifference = Math.abs(acc[0] - acc[1]);

    if (currentDifference < existingDifference) return [previosElement, element];
    if (currentDifference === existingDifference) return acc.concat(previosElement, element);

    return acc;
  }, startingPoint);
}

def closestNumbers(arr):
    # Write your code here
    arr.sort()
    min_abs = abs(arr[0] - arr[1])
    min_arr = [arr[0], arr[1]]
    for i in range(1, len(arr)-1):
        if abs(arr[i] - arr[i+1]) > min_abs:
            continue
        elif abs(arr[i] - arr[i+1]) == min_abs:
            min_arr.append(arr[i])
            min_arr.append(arr[i+1])
        elif abs(arr[i] - arr[i+1]) < min_abs:
            min_abs = abs(arr[i] - arr[i+1])
            min_arr = [arr[i], arr[i+1]]
    return min_arr

function closestNumbers(arr: number[]): number[] {
    /**
     * simple
     * 
     * 1. find [arr_sorted], sorted array of the [arr]
     * 2. find [min_diff], smallest difference between 2 adj element in [arr_sorted]
     * 3. loop [arr_sorted], only take pair that have difference smallest
     * 4. return
     */
    let arr_sorted = arr.sort((a, b) => a - b)

    let min_diff = null
    for (let i = 0; i < arr_sorted.length - 1; i++) {
        let pair = [arr_sorted[i], arr_sorted[i + 1]]
        let diff = Math.abs(pair[0] - pair[1])

        if (!min_diff || diff < min_diff) min_diff = diff
    }

    let pairs = []
    for (let i = 0; i < arr_sorted.length - 1; i++) {
        let pair = [arr_sorted[i], arr_sorted[i + 1]]
        let diff = Math.abs(pair[0] - pair[1])

        if (diff == min_diff) pairs.push(...pair)
    }

    return pairs;
}

D = {}
    arr = sorted(arr)
    mini = 10e6
    for i in range(len(arr) -1):
        diff = arr[i+1] - arr[i]
        if diff < mini: 
            mini = diff
            D[diff] = [arr[i+1], arr[i]]
        elif diff == mini:
            D[diff].extend([arr[i+1], arr[i]])
    
    result = sorted(D[mini])       
    return result