def AddTreeNode(self, preorder, prestart, preend, inorder, instart, inend):
nodesLen = preend - prestart
if nodesLen == 0: return None
elif nodesLen == 1: return TreeNode(preorder[prestart])
root = TreeNode(preorder[prestart])
rootIdx = inorder.index(preorder[prestart]) - instart
root.left = self.AddTreeNode(preorder, prestart+1, prestart+rootIdx+1, inorder, instart, instart+rootIdx)
root.right = self.AddTreeNode(preorder, prestart+rootIdx+1, preend, inorder, instart+rootIdx+1, inend)
return root
def main():
solver = Solver()
root = TreeNode(3)
root.left = TreeNode(9)
root.right = TreeNode(20)
root.right.left = TreeNode(15)
root.right.right = TreeNode(7)
print(solver.max_depth(root))
def AddTreeNode(self, preorder, prestart, preend, inorder, instart, inend):
nodesLen = preend - prestart
if nodesLen == 0: return None
elif nodesLen == 1: return TreeNode(preorder[prestart])
root = TreeNode(preorder[prestart])
rootIdx = inorder.index(preorder[prestart]) - instart
root.left = self.AddTreeNode(preorder, prestart + 1,
prestart + rootIdx + 1, inorder, instart,
instart + rootIdx)
root.right = self.AddTreeNode(preorder, prestart + rootIdx + 1, preend,
inorder, instart + rootIdx + 1, inend)
return root
def solution(self, nums):
"""
:type nums: List[int]
:rtype: TreeNode
"""
numsLen = len(nums)
if numsLen == 0:
return None
elif numsLen == 1:
return TreeNode(nums[0])
else:
root = TreeNode(nums[numsLen / 2])
root.left = self.solution(nums[:numsLen / 2])
root.right = self.solution(nums[numsLen / 2 + 1:])
return root
def solution(self, preorder, inorder): # not memory efficient since every recursive created new preorder/inorder lists
"""
:type preorder: List[int]
:type inorder: List[int]
:rtype: TreeNode
"""
nodeLen = len(preorder)
if nodeLen == 0: return None
elif nodeLen == 1: return TreeNode(preorder[0])
root = TreeNode(preorder[0])
for rootIdx in range(nodeLen):
if inorder[rootIdx] == preorder[0]: break
root.left = self.solution(preorder[1:rootIdx+1], inorder[:rootIdx])
root.right = self.solution(preorder[rootIdx+1:], inorder[rootIdx+1:])
return root
def solution(
self, preorder, inorder
): # not memory efficient since every recursive created new preorder/inorder lists
"""
:type preorder: List[int]
:type inorder: List[int]
:rtype: TreeNode
"""
nodeLen = len(preorder)
if nodeLen == 0: return None
elif nodeLen == 1: return TreeNode(preorder[0])
root = TreeNode(preorder[0])
for rootIdx in range(nodeLen):
if inorder[rootIdx] == preorder[0]: break
root.left = self.solution(preorder[1:rootIdx + 1], inorder[:rootIdx])
root.right = self.solution(preorder[rootIdx + 1:],
inorder[rootIdx + 1:])
return root
