Coderforces Helpful Maths

http://codeforces.com/problemset/problem/339/A

import java.util.Arrays;import java.util.Scanner;public class Helpful_Maths {public static void main(String[] args) {Scanner scanner = new Scanner(System.in);char[] ch = scanner.next().toCharArray();int n = ch.length;if(n == 1) System.out.println(ch[0]);else {int[] a = new int[100];int k = 0;for(int i = 0; i < n; i+=2) {a[k++] = ch[i] - '0';}int[] aa = new int[k];System.arraycopy(a, 0, aa, 0, k);Arrays.sort(aa);StringBuilder stringBuilder = new StringBuilder();int j = 0;for(int i = 1; i < n; i+=2) {stringBuilder.append(aa[j++]);stringBuilder.append(ch[i]);}stringBuilder.append(aa[k-1]);System.out.println(stringBuilder.toString());}}}