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Question18.java
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Question18.java
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//Find the longest palindrome substring
public class Question18 {
public String longestPalindrome(String s){
if(s == null || s.length() < 1) return "";
int start = 0;
int end = 0;
for(int i=0;i<s.length();i++){
int len1 = expandFromMiddle(s, i, i);
int len2 = expandFromMiddle(s, i, i+1);
int len = Math.max(len1, len2);
if(len > (end-start)){
start = i - ((len-1)/2);
end = i+(len/2);
}
}
return s.substring(start, end+1);
}
public int expandFromMiddle(String s, int left, int right){
if(s == null || left>right){
return 0;
}
while(left >= 0 && right < s.length() && s.charAt(left) == s.charAt(right)){
left --;
right++;
}
return right-left+1;
}
}