def buildTree(self, preorder, inorder):
"""
:type preorder: List[int]
:type inorder: List[int]
:rtype: TreeNode
"""
# preorder root left right
# inorder left root right
if len(preorder) == 0:
return None
if len(preorder) == 1:
return TreeNode(preorder[0])
# find the root in the inorder
in_root_idx = inorder.index(preorder[0])
left_tree = self.buildTree(preorder[1:in_root_idx + 1],
inorder[0:in_root_idx])
right_tree = self.buildTree(preorder[in_root_idx + 1:],
inorder[in_root_idx + 1:])
tn = TreeNode(preorder[0])
tn.left = left_tree
tn.right = right_tree
return tn
def buildTree(self, preorder, inorder):
# 128ms
if inorder:
ind = inorder.index(preorder.pop(0))
root = TreeNode(inorder[ind])
root.left = self.buildTree(preorder, inorder[0:ind])
root.right = self.buildTree(preorder, inorder[ind + 1:])
return root
def helper(node: TreeNode, val: int):
if node is None:
node = TreeNode(val)
return node
if val < node.val:
node.left = helper(node.left, val)
else:
node.right = helper(node.right, val)
return node
def constructMaximumBinaryTree(self, nums: List[int]) -> TreeNode:
# 228ms
if len(nums) == 0:
return None
i, n = self.maxnode(nums)
node = TreeNode(n)
node.left = self.constructMaximumBinaryTree(nums[:i])
node.right = self.constructMaximumBinaryTree(nums[i + 1:])
return node
def dfs(node: TreeNode):
if node is None:
return None
if node.left:
node.left = dfs(node.left)
if node.right:
node.right = dfs(node.right)
if node.val == target and node.left is None and node.right is None:
node = None
return node
def sortedArrayToBST(self, nums):
if nums == []:
return None
pos = len(nums) // 2
node = TreeNode(nums[pos])
if pos > 0:
node.left = self.sortedArrayToBST(nums[0:pos])
if pos > 0 and pos + 1 < len(nums):
node.right = self.sortedArrayToBST(nums[pos + 1:])
return node
def removeLeafNodes(self, root: TreeNode, target: int) -> TreeNode:
# 52ms
if root is None:
return None
if root.left:
root.left = self.removeLeafNodes(root.left, target)
if root.right:
root.right = self.removeLeafNodes(root.right, target)
if root.val == target and root.left is None and root.right is None:
root = None
return root
def arrayToBST(self, a):
if len(a) == 0:
return None
if len(a) == 1:
return TreeNode(a[0])
mid = len(a) // 2
tn = TreeNode(a[mid])
left = self.arrayToBST(a[0:mid])
right = self.arrayToBST(a[mid + 1:])
tn.left = left
tn.right = right
return tn
def insertIntoBST(self, root, val):
# 124ms
if root is None:
return TreeNode(val)
if val < root.val:
if root.left is None:
root.left = TreeNode(val)
else:
self.insertIntoBST(root.left, val)
else:
if root.right is None:
root.right = TreeNode(val)
else:
self.insertIntoBST(root.right, val)
return root
def helper(var_n: int) -> List[Optional[TreeNode]]:
if var_n in dp:
return dp[var_n]
result = []
for i in range(1, var_n - 2 + 1):
left_trees = helper(i)
right_trees = helper(var_n - i - 1)
for tree_l in left_trees:
for tree_r in right_trees:
root = TreeNode()
root.left = tree_l
root.right = tree_r
result.append(root)
dp[var_n] = result
return result
def setval(self, node):
for i in range(len(self.results)):
node.val = self.results[i]
node.left = None
if not node.right and i < len(self.results) - 1:
node.right = TreeNode(0)
node = node.right
def construct(l, r):
if l > r:
return
elif l == r:
return TreeNode(nums[l])
maximum = -float('inf')
for i in range(l, r + 1):
if maximum < nums[i]:
maximum = nums[i]
max_index = i
left = construct(l, max_index - 1)
right = construct(max_index + 1, r)
root = TreeNode(maximum)
root.left = left
root.right = right
return root
def generate(left: int, right: int):
if right - left < 0:
return [None]
elif right - left == 0:
return [TreeNode(left)]
else:
res = []
for curr in range(left, right + 1):
leftChild = generate(left, curr - 1)
rightChild = generate(curr + 1, right)
for l in leftChild:
for r in rightChild:
root = TreeNode(curr)
root.left = l
root.right = r
res.append(root)
return res
def allPossibleFBT(self, n: int) -> List[Optional[TreeNode]]:
# 216ms
ans = []
if n % 2 == 0:
return ans
if n == 1:
ans.append(TreeNode(0))
return ans
for i in range(1, n, 2):
Ll = self.allPossibleFBT(i)
Lr = self.allPossibleFBT(n - 1 - i)
for node_l in Ll:
for node_r in Lr:
node = TreeNode(0)
node.left = node_l
node.right = node_r
ans.append(node)
return ans
def deleteNode(self, root: TreeNode, key: int) -> TreeNode:
# 76ms
if not root:
return root
if root.val > key:
root.left = self.deleteNode(root.left, key)
elif root.val < key:
root.right = self.deleteNode(root.right, key)
else:
if not root.right:
return root.left
if not root.left:
return root.right
temp = root.right
mini = temp.val
while temp.left:
temp = temp.left
mini = temp.val
root.val = mini
root.right = self.deleteNode(root.right, root.val)
return root
def put(self, key, value):
"""
:type key: int
:type value: int
:rtype: void
"""
if self.get(key) != -1:
self.head.val = (key, value)
else:
node = TreeNode((key, value))
node.left = None
node.right = self.head
self.head.left = node
self.head = node
if self.tail.val[0] in self.h:
del self.h[self.tail.val[0]]
self.tail = self.tail.left
self.tail.right = None
self.h[self.head.val[0]] = self.head
def addOneRowSub(root: TreeNode, v: int, d: int, n: int,
isLeft: bool) -> TreeNode:
if root is None:
return None
if n == d:
temp = root
root = TreeNode(v)
if isLeft:
root.left = temp
else:
root.right = temp
if root.left is not None:
root.left = addOneRowSub(root.left, v, d, n + 1, True)
elif n + 1 == d:
root.left = TreeNode(v)
if root.right is not None:
root.right = addOneRowSub(root.right, v, d, n + 1, False)
elif n + 1 == d:
root.right = TreeNode(v)
return root
def flatten(self, root: TreeNode) -> None:
"""
Do not return anything, modify root in-place instead.
"""
# 40ms
if not root:
return
self.prev = root
self.flatten(root.left)
temp = root.right
root.right, root.left = root.left, None
self.prev.right = temp
self.flatten(temp)
def buildTree(self, inorder, postorder):
"""
:type inorder: List[int]
:type postorder: List[int]
:rtype: TreeNode
"""
if len(inorder) == 0:
return None
if len(inorder) == 1:
return TreeNode(inorder[0])
# inorder left root right
# postorder left right root
n = len(postorder)
root = postorder[n-1]
root_idx = inorder.index(root)
left_tree = self.buildTree(
inorder[0:root_idx], postorder[0:root_idx])
right_tree = self.buildTree(
inorder[root_idx+1:], postorder[root_idx:-1])
tn = TreeNode(root)
tn.left = left_tree
tn.right = right_tree
return tn
def helper(self, a):
if len(a) == 1:
return [TreeNode(a[0])]
out = []
for i in range(0, len(a)):
if i == 0:
lt = [None]
else:
lt = self.helper(a[0:i])
if i == len(a) - 1:
rt = [None]
else:
rt = self.helper(a[i + 1:])
for ll in lt:
for rr in rt:
root = TreeNode(a[i])
root.left = ll
root.right = rr
out.append(root)
return out
def bstFromPreorder(self, preorder: List[int]) -> Optional[TreeNode]:
# 24ms
if preorder is None:
return None
def helper(node: TreeNode, val: int):
if node is None:
node = TreeNode(val)
return node
if val < node.val:
node.left = helper(node.left, val)
else:
node.right = helper(node.right, val)
return node
node = TreeNode(preorder[0])
for i in range(1, len(preorder)):
helper(node, preorder[i])
return node
def allPossibleFBT2(self, n: int) -> List[Optional[TreeNode]]:
# 180ms
dp = dict()
dp[1] = [TreeNode()]
def helper(var_n: int) -> List[Optional[TreeNode]]:
if var_n in dp:
return dp[var_n]
result = []
for i in range(1, var_n - 2 + 1):
left_trees = helper(i)
right_trees = helper(var_n - i - 1)
for tree_l in left_trees:
for tree_r in right_trees:
root = TreeNode()
root.left = tree_l
root.right = tree_r
result.append(root)
dp[var_n] = result
return result
return helper(n)
def addOneRow2(self, root: TreeNode, v: int, d: int) -> TreeNode:
# 48ms
if d == 1:
n = TreeNode(v)
n.left = root
return n
dep = 1
q = [root]
while dep != d - 1:
newq = []
for n in q:
if n.left:
newq.append(n.left)
if n.right:
newq.append(n.right)
q = newq
dep += 1
for n in q:
l, r = n.left, n.right
newl, newr = TreeNode(v), TreeNode(v)
newl.left, newr.right = l, r
n.left, n.right = newl, newr
return root
def __init__(self, capacity):
"""
:type capacity: int
"""
out = []
for i in range(0, capacity):
out.append(TreeNode(("num{}".format(i), None)))
for i in range(0, capacity):
if i == 0:
out[i].left = None
else:
out[i].left = out[i - 1]
if i == capacity - 1:
out[i].right = None
else:
out[i].right = out[i + 1]
self.head = out[0]
self.tail = out[-1]
self.h = {}
path = []
self.helper(root, sum, path, out)
return out
def helper(self, root, sum, path, out):
if root is None:
if sum == 0:
out.append(path[:])
return
path.append(root.val)
if root.left is None and root.right is None:
if sum - root.val == 0:
out.append(path[:])
else:
if root.left is not None:
self.helper(root.left, sum - root.val, path, out)
if root.right is not None:
self.helper(root.right, sum - root.val, path, out)
path.pop()
return
test = False
if test:
from TreeNode.TreeNode import arrayToTreeNode, TreeNode
tn = arrayToTreeNode([5, 4, 8, 11, None, 13, 4, 7, 2, None, None, 5, 1])
tmp = TreeNode(0)
s = Solution()
print(s.pathSum(tn, 22))
def mergeTrees(self, t1, t2):
if not t1 and not t2: return None
ans = TreeNode((t1.val if t1 else 0) + (t2.val if t2 else 0))
ans.left = self.mergeTrees(t1 and t1.left, t2 and t2.left)
ans.right = self.mergeTrees(t1 and t1.right, t2 and t2.right)
return ans
def mergeTrees_work(self, t1, t2):
"""
:type t1: TreeNode
:type t2: TreeNode
:rtype: TreeNode
"""
if t1 is None and t2 is None:
return None
elif t1 is not None and t2 is not None:
node = TreeNode(t1.val + t2.val)
node.left = self.mergeTrees(t1.left, t2.left)
node.right = self.mergeTrees(t1.right, t2.right)
elif t1 is not None:
node = TreeNode(t1.val)
node.left = self.mergeTrees(t1.left, None)
node.right = self.mergeTrees(t1.right, None)
elif t2 is not None:
node = TreeNode(t2.val)
node.left = self.mergeTrees(None, t2.left)
node.right = self.mergeTrees(None, t2.right)
return node