manacher算法之最大回文子串

#include
#include
#include
using namespace std;
string Manacher(string &s)//预处理偶数回文。比如讲abba处理成#a#b#b#a#,这样就形成以#为对称轴的回文串
{
	string manachers("#");
	for (int i = 0; i < s.length();i++)
	{
		manachers.push_back(s[i]);
		manachers.push_back('#');
	}
	cout << manachers << endl;
	return manachers;
}

int MaxLcpLen(string str)
{
	string s = str;
	if (str.length() == 0)return 0;
	if (str.length() % 2 == 0)	
		 s = Manacher(str);//偶数回文转换成奇数回文，不影响结果
	int *pArr = new int[s.length()];//保存每个字符的回文半径
	int pR = -1;//之前遍历的字符的最大回文半径最右端的下一个字符
	int index = -1;
	for (int i = 0; i  < s.length();++i)
	{
		pArr[i] = pR > i ? min(pArr[2*index - i], pR - i) :1;
		while (i + pArr[i] < s.length() && i - pArr[i] > -1){
			if (s[i + pArr[i]] == s[i - pArr[i]])
				pArr[i]++;
			else
				break;
		}
		if (i + pArr[i] > pR){
			index = i;
			pR = i + pArr[i];
		}
	}
	return *max_element(pArr, pArr + s.length());
}
void main()
{ 
	string s = "abc1234321ab";
	cout << MaxLcpLen(s)- 1  << endl;
	cin.get();
}