s型打印二叉树

//S型层次遍历
public void levelSOrder(BinaryTreeNode p){
    Stack<BinaryTreeNode> stack1 = new Stack<>();
    Stack<BinaryTreeNode> stack2 = new Stack<>();
    int currentLevel = 1;
    if(p != null){
        stack1.push(p);
    }

    while(!stack1.isEmpty() || !stack2.isEmpty()){
        int levelNumber = !stack1.isEmpty()?stack1.size():stack2.size();
        for(int i = 0;i < levelNumber;i++){
            if((currentLevel & 1) == 1){
                p = stack1.pop();
                System.out.print(p.data + " ");
                if(p.right != null){
                    stack2.push(p.right);
                }
                if(p.left != null){
                    stack2.push(p.left);
                }
                if(stack1.empty()){
                    currentLevel++;
                }
            }else {
                p = stack2.pop();
                System.out.print(p.data + " ");
                if(p.left != null){
                    stack1.push(p.left);
                }
                if(p.right != null){
                    stack1.push(p.right);
                }
                if(stack2.empty()){
                    currentLevel++;
                }
            }
        }
        System.out.println();
    }
}