Given a string, determine if it is a palindrome, considering only alphanumeric characters and ignoring cases. For example, "A man, a plan, a canal: Panama" is a palindrome. "race a car" is not a palindrome. Note: Have you consider that…
问题描述 Given a string S, find the longest palindromic substring in S. You may assume that the maximum length of S is 1000, and there exists one unique longest palindromic substring. 所谓回文字符串,就是一个字符串,从左到右读和从右到左读是完全一样的.比如"a" , "aaabbaaa" 之前…