def to_binary_tree_distinct_vals(lst):
"""
To build a binary tree
:param lst: list of list
[[root, left, right], [root, left, right]]
:return: head
"""
tree_dict = dict() # val : TreeNode(val)
for node in lst:
tree_dict[node[0]] = tree_dict.get(node[0], TreeNode(node[0]))
left_child = None
if node[1] is not None:
tree_dict[node[1]] = tree_dict.get(node[1], TreeNode(node[1]))
left_child = tree_dict[node[1]]
right_child = None
if node[2] is not None:
tree_dict[node[2]] = tree_dict.get(node[2], TreeNode(node[2]))
right_child = tree_dict[node[2]]
tree_dict[node[0]].left = left_child
tree_dict[node[0]].right = right_child
return tree_dict[lst[0][0]]
def helper(ins, ine, pts, pte):
if ins > ine: return None
root = TreeNode(postorder[pte])
iroot = inorder.index(postorder[pte])
jroot = iroot - ins + pts
root.left = helper(ins, iroot - 1, pts, jroot - 1)
root.right = helper(iroot + 1, ine, jroot, pte - 1)
return root
def builder(self, insi, inei, preidx):
if insi > inei: return None
idx = self.lkp[self.preorder[preidx]]
"""while self.inorder[idx] != self.preorder[preidx]:
idx += 1"""
node = TreeNode(self.preorder[preidx])
node.left = self.builder(insi, idx - 1, preidx + 1)
node.right = self.builder(idx + 1, inei, preidx + idx - insi + 1)
return node
def __get_tree_two__(self):
root = TreeNode(6)
root.left = TreeNode(4)
root.right = TreeNode(7)
cur_node = root.left
cur_node.left = TreeNode(1)
cur_node.right = TreeNode(5)
cur_node = root.right
cur_node.right = TreeNode(9)
return root
def __get_first_tree__(self):
root = TreeNode(6)
root.left = TreeNode(4)
root.right = TreeNode(7)
cur_node = root.left
cur_node.left = TreeNode(1)
cur_node.right = TreeNode(3)
cur_node = cur_node.right
cur_node.left = TreeNode(2)
return root
def __get_tree_three__(self):
root = TreeNode(5)
root.left = TreeNode(3)
root.right = TreeNode(6)
cur_node = root.left
cur_node.left = TreeNode(1)
cur_node.right = TreeNode(4)
cur_node = cur_node.left
cur_node.right = TreeNode(2)
return root
def __init__(self):
super(LowestCommonAncestorBstTestCases, self).__init__()
self.__add_test_case__(
"Test 1",
[self.__get_tree_one__(),
TreeNode(2), TreeNode(8)], TreeNode(6))
self.__add_test_case__(
"Test 2",
[self.__get_tree_one__(),
TreeNode(2), TreeNode(4)], TreeNode(2))
self.__add_test_case__(
"Test 3",
[self.__get_tree_one__(),
TreeNode(2), TreeNode(0)], TreeNode(2))
def __get_tree_one__(self):
root = TreeNode(3)
root.left = TreeNode(2)
root.right = TreeNode(3)
cur_node = root.left
cur_node.right = TreeNode(3)
cur_node = root.right
cur_node.right = TreeNode(1)
return root
def to_complete_binary_tree(lst):
"""
Complete Binary Tree
:param lst: a list of tree nodes
:return:
"""
n = len(lst)
if n < 1: return None
tree = [TreeNode(lst[0])]
for i in xrange(1, n):
pidx = int(math.floor((i - 1) / 2))
tree.append(TreeNode(lst[i]))
if tree[pidx].val == None or lst[i] == None:
continue
if i % 2 == 1:
tree[pidx].left = tree[i]
else:
tree[pidx].right = tree[i]
return tree[0]