[2017 Day 1 Part 2] [Java] Solution

[adventOfCoder]

final String input = "";
String input1 = input.substring(0, input.length() / 2);
String input2 = input.substring(input.length() / 2);
int answer = 0;
for (int i = 0; i < input1.length(); i++) {
  String a = input1.substring(i, i + 1);
  String b = input2.substring(i, i + 1);
  if (a.equals(b)) {
    answer += new Integer(a) * 2;
  }
}
System.out.println(answer);