Bit Manipulation

Leetcode - addBinary

• TODO: solve it with bit manipulation way too
• you can insert a int strictly into the stringbuilder. It gets converted to Integer and stringbuilder prints the integer object.

  public String addBinary(String first, String second) {
    int firstI = first.length() - 1;
    int secondI = second.length() - 1;
    StringBuilder result = new StringBuilder();
    int carry = 0;
    // carry can never be more than a base
    while (0 <= firstI || 0 <= secondI) {
      int x = firstI < 0 ? 0 : first.charAt(firstI) - '0';
      int y = secondI < 0 ? 0 : second.charAt(secondI) - '0';
      int sum = x + y + carry;
      carry = sum / 2;
      int val = sum % 2;
      result.insert(0, val);
      firstI--;   secondI--;
    }
    if (0 < carry) result.insert(0, carry);
    return result.toString();
  }