from typing import List


def arr_min_max(arr: List):
    """Find min and max element in arrray

    Args:
        arr (List): List from which min and max needs to be found

    Returns:
        list: List with first element as minimum and second as maximum
    """
    if len(arr) <=0:
        return []
    
    arr_min = arr[0]
    arr_max = arr[0]
    
    for ele in arr:
        if arr_min > ele:
            arr_min = ele
        if arr_max < ele:
            arr_max = ele
    
    return [arr_min, arr_max]