一文搞定二叉树遍历

result.append(root.val) self.helper(root.left,result) self.helper(root.right, result) # Recursive self.helper(root.left,result) result.append(root.val) self.helper(root.right, result) # Recursive self.helper(root.left,result) self.helper(root.right, result) result.append(root.val) # Recursive