def merge(t1, t2):
if not t1: return t2
if not t2: return t1
root = TreeNode(t1.val + t2.val)
root.left = merge(t1.left, t2.left)
root.right = merge(t1.right, t2.right)
return root
def addOneRow(root, v, d):
def attach(node, v, is_left=False):
new_node = TreeNode(v)
if is_left:
new_node.left = node
else:
new_node.right = node
return new_node
def search(root, depth):
if depth > d or root is None:
return root
if depth + 1 != d:
search(root.left, depth + 1)
search(root.right, depth + 1)
else:
root.left = attach(root.left, v, is_left=True)
root.right = attach(root.right, v, is_left=False)
return root
if 1 == d:
new_root = TreeNode(v)
new_root.left = root
return new_root
else:
return search(root, 1)
def attach(node, v, is_left=False):
new_node = TreeNode(v)
if is_left:
new_node.left = node
else:
new_node.right = node
return new_node
def build_tree(i, j):
if j < i: return None
max_val = nums[i]
max_idx = i
for idx in range(i + 1, j + 1):
val = nums[idx]
if val > max_val:
max_idx = idx
max_val = val
root = TreeNode(max_val)
root.left = build_tree(i, max_idx - 1)
root.right = build_tree(max_idx + 1, j)
return root