题目2 快乐消消乐

给定一个字符串将相邻的两个字符进行消除，最后返回消除后字符串的总长数

public int xxl(String content) {
    int length = 0;
    if (content == null || content.length() == 0) {
        return length;
    }
    char[] chars = content.toCharArray();
    Stack<String> sta = new Stack<String>();
    for (int i = 0; i < chars.length; i++) {
        char c= chars[i];
        if (!sta.isEmpty()&&sta.peek().equals(String.valueOf(c))){
            sta.pop();
        }else {
            sta.push(String.valueOf(c));
        }
    }
    return sta.size();
}