FisrtThenLastOrder.java

import java.util.ArrayList;
import java.util.LinkedList;
import java.util.List;
import java.util.Scanner;

public class FisrtThenLastOrder {

  public static void main(String... args) {
    Scanner scanner = new Scanner(System.in);
    int number = scanner.nextInt();
    System.out.println(solution(number));
  }

  private static int solution(int number) {
    List<Integer> numbers = orderedFrom(number);
    return merge(numbers);
  }

  private static int merge(List<Integer> numbers) {
    int number = 0;
    int n = numbers.size();
    for (int i = 0; i < n; i++) {
      int exp = n - i - 1;
      number += numbers.get(i) * Math.pow(10, exp);
    }
    return number;
  }

  private static List<Integer> orderedFrom(int number) {
    LinkedList<Integer> numbers = new LinkedList<>();
    while (number % 10 != number) {
      int result = number % 10;
      numbers.add(result);
      number = number / 10;
    }
    numbers.add(number);
    List<Integer> elements = new ArrayList<>();
    while (!numbers.isEmpty()) {
      if (!numbers.isEmpty()) elements.add(numbers.pollLast());
      if (!numbers.isEmpty()) elements.add(numbers.pollFirst());
    }
    return elements;
  }
}