[Classic] palindrome problem (iii)

Longest palindromic Substring longest palindrome substring

Given a string S, find the longest palindromic substring in s. The maximum length of S is assume, and there exists one unique longest palindromic substring.

General practice, Dynamic Planning O (n^2) is able to directly produce results, the length from small to large arrangement, you can record the maximum value of the edge motion.

Shortest palindrome Shortest palindrome generation

Given A string S, you is allowed to convert it to a palindrome by adding characters in front of it. Find and return the shortest palindrome you can find by performing this transformation.

For example:

Given "aacecaaa" , return "aaacecaaa" .

Given "abcd" , return "dcbabcd" .

Common practice, that is to find the longest palindrome from scratch, the complexity of O (n^2);

In fact, the classic algorithm for finding the longest palindrome substring centered on a point is the manacher algorithm, with the complexity of O (N), which can be used to find substrings centered on each point in the string. The Manacher algorithm can refer to http://blog.csdn.net/ggggiqnypgjg/article/details/6645824/

[Classic] palindrome problem (iii)