public int solution(String s)
{
    Stack<Character> stack = new Stack<>();

    for (int i = 0; i < s.length(); i++) {
        char toPush = s.charAt(i);
        if (!stack.isEmpty()) {
            Character peek = stack.peek();
            if (peek == toPush) {
                stack.pop();
                continue;
            }
        }
        stack.push(toPush);
    }

    out.println("stack = " + stack);

    if (stack.isEmpty()) {
        return 1;
    }
    return 0;
}

public int solution2(String s) {
    Stack<Character> stack = new Stack<>();
    for (char c : s.toCharArray()) {
        if (stack.isEmpty()) {
            stack.push(c);
        } else if (stack.peek() == c) {
            stack.pop();
        } else {
            stack.push(c);
        }
    }
    return stack.isEmpty() ? 1 : 0;
}