class Solution {
public String longestPalindrome(String s) {
if(s==null || s=="")
return "";
String ans="";
int a=s.length();
for(int i=0;i<a;i++){
String temp = findstr(s,i,i); //奇数序列
if(temp.length()>ans.length())
ans = temp;
temp = findstr(s,i,i+1); //偶数序列
if(temp.length()>ans.length())
ans = temp;
}
return ans;
}
String findstr(String s, int i, int j){
while(i>=0&&j<s.length()&&s.charAt(i)==s.charAt(j)){
i--;
j++;
}
return s.substring(i+1,j);
}
}