问减去数的反射直到零

EN

def my_func(x):
  while x != 0: # We stop when x is 0 since that is our destination
    print(f"number @ current step: {x}")
    x = abs(x - r(x)) # subtract the reflection and get rid of the negative sign (if it is negative)

# returns True if 0 is reached, False if it never reaches 0.
def my_func(x):
  cache = set()
  while x != 0: # We stop when x is 0 since that is our destination
    # print(f"number @ current step: {x}")
    x = abs(x - r(x)) # subtract the reflection and get rid of the negative sign (if it is negative)
    if x in cache:
      print(f"This number does not terminate!")
      return False
    cache.add(x)
  return True

def reflect(n):
    r = 0
    while n > 0:
        r *= 10
        r += n % 10
        n //= 10
    return r    

upper_bound = pow(10, 6) - 1

# Result cache for all tested numbers, pre-initialize the array with zeroes.
cache = [0 for i in range(upper_bound + 1)]

def test(n):
    if n == 0:
        return True
    if cache[n] == 1:
        # Early out because we already know n does converge.
        return True
    if cache[n] == 2:
        # Loop in current recursion detected, so n does not converge.
        cache[n] = 3
        return False
    if cache[n] == 3:
        # n has previously been marked as non-converging.
        cache[n] = 3
        return False
    # Temporarily mark numbers in current recursion (2)
    cache[n] = 2
    if test(abs(n - reflect(n))):
        # Mark n as converging (1).
        cache[n] = 1
        return True
    else:
        # Mark n as non-converging (3).
        cache[n] = 3
        return False
    
converging = 0
non_converging = 0
for i in range(1, upper_bound):
    if test(i):
        converging += 1
    else:
        non_converging += 1
print(f'{converging} converging and {non_converging} failing.')

def r(n):
    r = 0
    while n > 0:
        r *= 10
        r += n % 10
        n //= 10
    return r
    
input_number = 275
max_iters = 100 # don't want to run infinitely if it does not converge
iters = 0

while( input_number != 0 and iters < max_iters ):
   
    #debug, if you wish
    print(input_number, " - ", r((input_number)))
    input_number = abs( input_number - r(input_number))
    
    iters += 1