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  1. import java.util.*;
  2. import java.lang.*;
  3. import java.io.*;
  4.  
  5. /* Name of the class has to be "Main" only if the class is public. */
  6. class Codechef
  7. {
  8. 	public static void main (String[] args) throws java.lang.Exception
  9. 	{
  10. 		// your code goes here
  11. 	    BufferedReader br = new BufferedReader(new InputStreamReader(System.in));
  12. 		StringBuffer sb = new StringBuffer();
  13. 		while(true) {
  14. 			String s =br.readLine();
  15. 			if(s.length()==1&&s.charAt(0)=='0') break;
  16. 			int num=codeShef(s);
  17. 			if(num==-1) System.out.println("Impossible");
  18. 			else System.out.println(num);
  19. 		}
  20. 	}
  21. 		public static int codeShef(String s) {
  22. 		char[] ary=s.toCharArray();
  23. 		boolean valid=true;
  24. 		int res=0;
  25. 		int i=0, j=ary.length-1;
  26. 		while(i<j) {
  27. 			//System.out.println(i);
  28. 			//System.out.println(j);
  29. 			if(ary[i]==ary[j]) {
  30. 				i++;
  31. 				j--;
  32. 				continue;
  33. 			}
  34. 			boolean found=false;
  35. 			int si=i+1;
  36. 			int ej=j-1;
  37. 			while(si<j&&ej>i) {
  38. 				//System.out.println(si);
  39. 				if(ary[si]==ary[j]) {
  40. 					found=true;
  41. 					while(si>i) {
  42. 						res++;
  43. 						ary[si]=ary[si-1];
  44. 						si--;
  45. 					}
  46. 					ary[i]=ary[j];
  47. 					break;
  48. 				}
  49. 				if(ary[ej]==ary[i]) {
  50. 					while(ej<j) {
  51. 						res++;
  52. 						ary[ej]=ary[ej+1];
  53. 						ej++;
  54. 					}
  55. 					ary[j]=ary[i];
  56. 					found=true;
  57. 					break;
  58. 				}
  59. 				si++;
  60. 				ej--;
  61. 			}
  62. 			//System.out.println("eeee");
  63. 			if(!found) return -1;
  64. 			i++;
  65. 			j--;
  66.  
  67. 		}
  68. 		//System.out.println(new String(ary));
  69. 		return res;
  70.  
  71. 	}
  72.  
  73. }
Runtime error #stdin #stdout #stderr 0.08s 32660KB
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Standard input is empty
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Standard output is empty
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Exception in thread "main" java.lang.NullPointerException
	at Codechef.main(Main.java:15)
https://ideone.com/VM67ip
language:
Java (HotSpot 12)
created:
4 years ago
visibility:
public

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