project-euler36.java

public class Main {

    private static boolean isPalindrome (String string) {
        String reversedString = new StringBuilder(string).reverse().toString();

        for (int i =0; i < string.length() / 2; i++) {
            if (string.charAt(i) != reversedString.charAt(i))
                return false;
        }

        return true;
    }

    public static void main(String[] args) {
        long sum = 0;
        int upto = 1000000; // upto one million

        for(int num = 0; num < upto; num++) {
            String decimalString = Integer.toString(num);
            String binaryString = Integer.toBinaryString(num);

            if (isPalindrome(decimalString) && isPalindrome(binaryString)) {
                sum += num;
            }
        }

        System.out.println ("The sum of all palindromic number in both base 2" +
                " and base 10 under 1,000,0000 is " + sum);

    }
}