5. 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:

Input: "babad"

Output: "bab"

Note: "aba" is also a valid answer.

 

Example:

Input: "cbbd"

Output: "bb"

public class Solution {
public String longestPalindrome(String s) {
if (s.length() == 0) {
return s;
}

String result = "";
for (int i = 0; i < s.length(); i++) {
String temp = isPalidrome(s, i, i);
if (temp.length() > result.length()) {
result = temp;
}

temp = isPalidrome(s, i-1, i);
if (temp.length() > result.length()) {
result = temp;
}
}

return result;


}

public String isPalidrome(String s, int start, int end) {
if (start < 0 || end >= s.length()) {
return "";
}
while (start >= 0 && end < s.length()) {
if (s.charAt(start) == s.charAt(end)) {
start--;
end++;
} else {
break;
}
}

return s.substring(start+1, end);
}