def main():
solver = Solution()
for test in [[1, None, 2, None, None, 3]]:
root = TreeNode()
root.build_from_list(test)
print(solver.preorderTraversal(root))
pass
class Solution:
# @param root, a tree node
# @return a list of lists of integers
def levelOrderBottom(self, root):
if root is None:
return []
result = []
cur_level = [root]
next_level = []
while len(cur_level) > 0:
values = []
for node in cur_level:
values.append(node.val)
if node.left is not None:
next_level.append(node.left)
if node.right is not None:
next_level.append(node.right)
cur_level = next_level
next_level = []
result.append(values)
return result[::-1]
if __name__ == '__main__':
root = TreeNode()
root.build_from_list([3, 9, 20, None, None, 15, 7])
res = Solution().levelOrderBottom(root)
print(res)
# bfs
depth = 1
found_leaf = False
cur_depth = [root]
next_depth = []
while True:
next_depth = []
for node in cur_depth:
is_leaf = True
if node.left is not None:
next_depth.append(node.left)
is_leaf = False
if node.right is not None:
next_depth.append(node.right)
is_leaf = False
if is_leaf is True:
found_leaf = True
break
if found_leaf is True:
break
else:
depth += 1
cur_depth = next_depth
return depth
if __name__ == '__main__':
root = TreeNode()
root.build_from_list(list(range(10)))
print(Solution().minDepth(root))
ltail.left = None
ltail.right = None
return root, ltail
elif root.left is not None and root.right is not None:
lhead, ltail = gao(root.left)
rhead, rtail = gao(root.right)
root.left = None
root.right = lhead
lhead.left = None
ltail.left = None
ltail.right = rhead
rhead.left = None
rtail.left = None
rtail.right = None
return root, rtail
gao(root)
solver = Solution()
root5 = TreeNode()
root5.build_from_list([1,2,3,4])
solver.flatten(root5)
print(root5.to_dict())
root4 = TreeNode()
root4.build_from_list([2,1,4,None,None,3,5])
solver.flatten(root4)
print(root4.to_dict())
