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  1. import java.util.*;
  2. import java.lang.*;
  3. import java.io.*;
  4.  
  5. class Ideone
  6. {
  7. 	public static void main (String[] args) throws java.lang.Exception
  8. 	{
  9. 		System.out.println(shortestPalindrome("aacecaaa"));
  10. 		System.out.println(shortestPalindrome("aaacecaa"));
  11. 		System.out.println(shortestPalindrome("abcd"));
  12. 		System.out.println(shortestPalindrome("madamImadam"));
  13. 		System.out.println(shortestPalindrome("madaMimadam"));
  14. 	}
  15.  
  16.     private static Boolean IsPalindrome(String s) {
  17.         int midpoint = s.length()/2;
  18.         // If the string length is odd, we do not need to check the central character
  19.         // as it is common to both
  20.         return (new StringBuilder(s.substring(0, midpoint)).reverse().toString()
  21.                 .equals(s.substring(s.length() - midpoint)));
  22.     }
  23.  
  24. 	private static String shortestPalindrome(String s) {
  25.         int j = s.length();
  26.         while (!IsPalindrome(s.substring(0, j))) {
  27.         	j--;
  28.         }
  29.         String suffix = s.substring(j);
  30.         return new StringBuilder(suffix).reverse()
  31.                   .append(s.substring(0, j))
  32.                   .append(suffix)
  33.                   .toString(); 
  34. 	}     
  35. }
Success #stdin #stdout 0.09s 320512KB
comments (?)
stdin 
Standard input is empty
stdout 
aaacecaaa
aacecaaacecaa
dcbabcd
madamImadam
madamiMadamadaMimadam
https://ideone.com/KFEnwO
language:
Java (HotSpot 12)
created:
10 years ago
visibility:
public

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