inverse_of_number.java

/*  QUESTION:
1. The key constraint is if the number is 5 digits long, it'll contain all the digits from 1 to 5 without missing any and without repeating 
any. e.g. 23415 is a 5 digit long number containing all digits from 1 to 5 without missing and repeating any digit from 1 to 5.Take a look at few other valid numbers
- 624135, 81456273 etc.Here are a few invalid numbers - 139, 7421357 etc.
2. The inverse of a number is defined as the number created by interchanging the face value and index of digits of number.e.g. for 426135 (reading from right to left, 
5 is in place 1, 3 is in place 2, 1 is in place 3, 6 is in place 4, 2 is in place 5 and 4 is in place 6), the inverse will be 416253 (reading from right to left, 3 is 
in place 1, 5 is in place 2,2 is in place 3, 6 is in place 4, 1 is in place 5 and 4 is in place 6) More examples - inverse of 2134 is 1243 and inverse of 24153 is 24153    
3. Take as input number "n", assume that the number will follow constraints.
4. Print it's inverse.*/
// input=28346751
// output=73425681

import java.util.*;

public class Main{

public static void main(String[] args) {
  
  Scanner scn  = new Scanner(System.in);
  int n = scn.nextInt();
  int sum=0, count=0,temp;
  while(n > 0)
  {
      temp = n%10;
      count++;
      sum = sum + (count * (int)(Math.pow(10,temp-1))); 
      n = n/10;
  }
  System.out.println(sum);
 }
}