package question;

/*
 @author: Roderland
 @create: 2020年09月21日---22:44
*/
public class Question647 {
 public static void main(String[] args) {
 String s = "aba";
 new Question647().countSubstrings(s);
 }

 public int countSubstrings(String s) {
 int count = s.length();
 boolean[] flags = new boolean[s.length() - 1];
 for (int i = 2; i <= s.length(); i += 2) {
 for (int j = 0; j + i - 1 < s.length(); j++) {
 if (s.charAt(j) == s.charAt(j + i - 1) && !flags[i / 2 + j - 1]) count++;
 else flags[i / 2 + j - 1] = true;
 }
 }
 for (int i = 0; i < flags.length; i++) flags[i] = false;
 for (int i = 3; i <= s.length(); i += 2) {
 for (int j = 0; j + i - 1 < s.length(); j++) {
 if (s.charAt(j) == s.charAt(j + i - 1) && !flags[i / 2 + j]) count++;
 else flags[i / 2 + j] = true;
 }

 }
 return count;
 }
}