def _constructHelper(self, iStart, iEnd):
if iEnd < iStart:
return None
root = BinaryTree(self._postorder[self.pIndex])
self.pIndex -= 1
if iStart == iEnd:
return root
inIndex = self._inorder.index(root.getRootVal())
root.setRightChild(self._constructHelper(inIndex + 1, iEnd))
root.setLeftChild(self._constructHelper(iStart, inIndex - 1))
return root
def _constructHelper(self, levelorder, inorder):
if not levelorder:
return None
root = BinaryTree(levelorder[0])
if len(levelorder) == 1:
return root
inIndex = inorder.index(root.getRootVal())
left = inorder[:inIndex]
right = inorder[inIndex+1:]
root.setLeftChild(self._constructHelper(self._getSubList(levelorder, left), left))
root.setRightChild(self._constructHelper(self._getSubList(levelorder, right), right))
return root