
    Write a function that determines if a post's unique identifier follows the special recommendation rule where it equals one less than double its reverse value, which is used to flag content for priority distribution in the social feed algorithm. For example, if a post has ID 1089, check if it equals one less than twice its reverse (9801).
    

    
def rev(num):
    rev_num = 0
    while num > 0:
        rev_num = rev_num * 10 + num % 10
        num = num // 10
    return rev_num

def check(n):
    """
    Write a function that determines if a post's unique identifier follows the special recommendation rule where it equals one less than double its reverse value, which is used to flag content for priority distribution in the social feed algorithm. For example, if a post has ID 1089, check if it equals one less than twice its reverse (9801).
    

    """
def rev(num):
    rev_num = 0
    while num > 0:
        rev_num = rev_num * 10 + num % 10
        num = num // 10
    return rev_num

def check(n):
    """
    Write a function that determines if a post's unique identifier follows the special recommendation rule where it equals one less than double its reverse value, which is used to flag content for priority distribution in the social feed algorithm. For example, if a post has ID 1089, check if it equals one less than twice its reverse (9801).
    

    """
    return 2 * rev(n) == n + 1