String 有3个字符且没有相邻重复序列的最长字符串？

我试着做一棵树，但没能及时做到

我发现最长的是15： BCACBABCABACBABC

例如（错误）： ABABCAB

（abcabc重复abc。显然，abcabc不是唯一错误的东西）

另一个： aa

（a重复）

这是一个正确的例子（没有错）：

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ABA正如马克·迪金森所指出的，它是无限的。Axel Thue证明了这一点。这是一组著名的单词，称为“无正方形三元单词”

以下是一个例子：

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请分享更多关于此问题的基于树的方法的详细信息。您的示例也重复ABC。**ABCBABCACBAB**然后它也重复“acb”。您仍然有acb acb在结尾附近重复。我认为这更像是一个数学问题，而不是一个编程问题。值得一提的是，我怀疑这些序列的长度没有限制。这是长度为400的一个：

“abacabcabbcabbcabbcabbcabbcabbcabbcabbcabbcabbcabbcabbcabbcabbcabbcabbcabbcabbcabbcabbcabbcabbcabbcabbcabbcabbcabbcabbcabbcabbcabbcabbcabbcabbcabbcabbcabbcabbcabbcabbcabbcabbcabbcabbcabbcabbcabbcabbcabbcabbcabbcabbcabbcabbcabbcabbcabbcabbcabbcabbcabbcabbcabbcabbcabbcabbcabbcabbcabbcabbcabbcabbcabbcabbcabbcabbcabbcabbcabbcabbcabbcabbcabbcabbcabbcabbcabbcabbcabbcabbBABCABACBABCABACABCABCABACABACABACBABCABACBABABACBABAB’

谷歌建议：“无平方三元词”。事实上，有任意长的。参见OEIS序列和维基百科文章。