Palindrome

刘子淼

于 2019-07-21 18:53:06 发布

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分类专栏：最长公共子序列滚动数组文章标签：最长公共子序列滚动数组

本文链接：https://blog.youkuaiyun.com/rg_lzm/article/details/96747532

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本文介绍如何利用最长公共子序列和滚动数组技术解决将字符串转化为回文的最小插入字符数问题。给出样例输入输出，并详细解释算法思路，包括将输入字符串倒置并与原字符串比较，计算最大公共子序列，最后通过滚动数组优化空间复杂度。

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Palindrome（最长公共子序列滚动数组）链接

A palindrome is a symmetrical string, that is, a string read identically from left to right as well as from right to left. You are to write a program which, given a string, determines the minimal number of characters to be inserted into the string in order to obtain a palindrome.

As an example, by inserting 2 characters, the string “Ab3bd” can be transformed into a palindrome (“dAb3bAd” or “Adb3bdA”). However, inserting fewer than 2 characters does not produce a palindrome.
Input
Your program is to read from standard input. The first line contains one integer: the length of the input string N, 3 <= N <= 5000. The second line contains one string with length N. The string is formed from uppercase letters from ‘A’ to ‘Z’, lowercase letters from ‘a’ to ‘z’ and digits from