https://leetcode.com/problems/longest-palindromic-substring/
Given a string s, find the longest palindromic substring in s. You may assume that the maximum length of s is 1000.
Example 1:
Input: "babad" Output: "bab" Note: "aba" is also a valid answer.
Example 2:
Input: "cbbd" Output: "bb"
题解：$Manacher‘s Algorithm$ 马拉车算法 用 $O(n)$ 的时间复杂度来判断最长回文子串的长度
详解：https://www.cnblogs.com/grandyang/p/4475985.html
代码：
class Solution {
public:
string longestPalindrome(string s) {
string t = "$#";
for(int i = 0; i < s.length(); i ++) {
t += s[i];
t += "#";
}
vector<int> p(t.size(), 0);
int mx = 0, id = 0, resLen = 0, resCenter = 0;
for(int i = 0; i < t.size(); i ++) {
p[i] = mx > i ? min(p[2 * id - i], mx - i) : 1;
while (t[i + p[i]] == t[i - p[i]]) ++p[i];
if (mx < i + p[i]) {
mx = i + p[i];
id = i;
}
if (resLen < p[i]) {
resLen = p[i];
resCenter = i;
}
}
return s.substr((resCenter - resLen) / 2, resLen - 1);
}
};
#Leetcode# 5. Longest Palindromic Substring
原文：https://www.cnblogs.com/zlrrrr/p/9983095.html