class Solution: def Convert(self , pRootOfTree ): if not pRootOfTree: return None def inorder(root): if not root: return [] return inorder(root.left) + [root] + inorder(root.right) tmp = inorder(pRootOfTree) for i in range(len(tmp) - 1): tmp[i].right = tmp[i+1] tmp[i+1].left = tmp[i] return tmp[0]