import java.util.*;
 
    class Solution {
        /*
         * param number: A 3-digit number.
         * return: Reversed number.
         */
        public int reverseInteger(int number) {
            // write your code here
            if (number > 1000 || number <100){
                return -1;
            }
            String s = Integer.toString(number);
            char[] c = s.toCharArray();
            StringBuilder b = new StringBuilder(c.length);
 
            for (int i = s.length()-1; i >= 0; i--){
                b.append(String.valueOf(c[i]));
            }
 
            int y = Integer.parseInt(b.toString());
            return y;
        }
 
        public static void main(String args[]) {
            Solution p = new Solution();
            int ff= p.reverseInteger(102);
            System.out.println(ff); // 201
        }
    }

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