剑指offer 58.树 对称的二叉树

boolean isSymmetrical(TreeNode pRoot)
    {    boolean flag=true;
        if (pRoot==null||(pRoot.left==null&&pRoot.right==null)) {
            return true;
        }
        TreeNode leftNode=pRoot.left;
        TreeNode rightNode=pRoot.right;
        
        return comRoot(leftNode,rightNode);
        
    }

    private boolean comRoot(TreeNode leftNode, TreeNode rightNode) {
        if(leftNode == null) return rightNode==null;
        if(rightNode == null) return false;
        if (leftNode.val!=rightNode.val) {
            return false;
        }
        
        return comRoot(leftNode.right, rightNode.left)&&comRoot(leftNode.left, rightNode.right);
    }