python - 我的 Lychrel 号码查找器有什么问题？

Question

我正在尝试解决 Project Euler problem #55 ，其中指出:

If we take 47, reverse and add, 47 + 74 = 121, which is palindromic.

Not all numbers produce palindromes so quickly. For example,

349 + 943 = 1292, 1292 + 2921 = 4213, 4213 + 3124 = 7337

That is, 349 took three iterations to arrive at a palindrome.

Although no one has proved it yet, it is thought that some numbers, like 196, never produce a palindrome. A number that never forms a palindrome through the reverse and add process is called a Lychrel number. Due to the theoretical nature of these numbers, and for the purpose of this problem, we shall assume that a number is Lychrel until proven otherwise. In addition you are given that for every number below ten-thousand, it will either (i) become a palindrome in less than fifty iterations, or, (ii) no one, with all the computing power that exists, has managed so far to map it to a palindrome. In fact, 10677 is the first number to be shown to require over fifty iterations before producing a palindrome: 4668731596684224866951378664 (53 iterations, 28-digits).

Surprisingly, there are palindromic numbers that are themselves Lychrel numbers; the first example is 4994.

How many Lychrel numbers are there below ten-thousand?

TL;DR:如果数字不是回文，则将其添加到自身的反面。仍然没有？重复。 ...50 次迭代后... 这是一个 Lychrel 数。

我的代码:

def isPalindrome(n):
    return str(n)[::-1] == str(n)

lychrels = 0

for i in range(1,10000):
    lychrel = True
    for j in range(50):
        if isPalindrome(i):
            lychrel = False
            break

        else:
            i += int(str(i)[::-1])

    if lychrel:
        lychrels += 1

print(lychrels)

它适用于 349(非 Lychrel)和 196(Lychrel)的测试用例，但 Project Euler 拒绝了我得到的答案。

我还没有解决这个问题，所以我更喜欢提示而不是直接的解决方案。

我做错了什么？

Answer 1

您错误地假设了一个以回文开头而不是 lychrel 的数字。我认为这是你唯一的错误。