def enQueue(self, value: int) -> bool:
if self.isFull():
return False
if self.isEmpty():
self.head = Node(value)
self.tail = self.head
else:
newNode = Node(value)
self.tail.next = newNode
self.tail = newNode
self.size += 1
return True
def cloneGraph(self, node: 'Node') -> 'Node':
if node is None:
return None
cloned_node = Node(node.val)
cloned_dict, queue = {node: cloned_node}, [node]
while queue:
current = queue.pop()
for neighbor in current.neighbors:
if neighbor not in cloned_dict:
queue.append(neighbor)
cloned_neighbor = Node(neighbor.val)
cloned_dict[neighbor] = cloned_neighbor
cloned_dict[current].neighbors.append(cloned_dict[neighbor])
return cloned_dict[node]
def copyRandomList(self, head: 'Node') -> 'Node':
dummy = Node(-1)
current, prev, copies = head, dummy, {}
while current:
copied = Node(current.val)
copies[current] = copied
prev.next = copied
prev, current = prev.next, current.next
current = head
while current:
if current.random:
copies[current].random = copies[current.random]
current = current.next
return dummy.next
def flatten(self, head):
if not head:
return
pseudoHead = Node(0, None, head, None)
prev = pseudoHead
stack = []
stack.append(head)
while stack:
curr = stack.pop()
prev.next = curr
curr.prev = prev
if curr.next:
stack.append(curr.next)
if curr.child:
stack.append(curr.child)
# don't forget to remove all child pointers.
curr.child = None
prev = curr
# detach the pseudo head node from the result.
pseudoHead.next.prev = None
return pseudoHead.next
def dfs(self, head, node_list):
if not head or head.val is None:
return
node_list.append(Node(head.val))
if head.child:
cld = head.child
head.child = None
self.dfs(cld, node_list)
self.dfs(head.next, node_list)
def test_solution():
samples = [[[7, None], [13, 0], [11, 4], [10, 2], [1, 0]], [[1, 1], [2,
1]],
[[3, None], [3, 0], [3, None]], []]
lists = [Node.initList(x) for x in samples]
# res = [sol.copyRandomList(x) for x in lists]
res = [Solution().copyRandomList(x) for x in lists]
res1 = [Solution1().copyRandomList(x) for x in lists]
assert repr(lists) == repr(res)
assert repr(lists) == repr(res1)
def flatten(self, head):
if not head:
return head
# pseudo head to ensure the `prev` pointer is never none
pseudoHead = Node(None, None, head, None)
self.flatten_dfs(pseudoHead, head)
# detach the pseudo head from the real head
pseudoHead.next.prev = None
return pseudoHead.next
def copyRandomList(self, head: 'Node') -> 'Node':
if not head:
return head
clone = defaultdict(lambda: Node(0))
clone[None] = None
cur = head
while cur:
clone[cur].val = cur.val
clone[cur].next = clone[cur.next]
clone[cur].random = clone[cur.random]
cur = cur.next
return clone[head]
def solve(self, data):
num = 0
while data[self.pos].isdigit():
num *= 10
num += ord(data[self.pos]) - ord('0')
self.pos += 1
node = Node(num, [])
while self.pos < len(data):
if data[self.pos] == '[':
self.pos += 1
node.children.append(self.solve(data))
elif data[self.pos] == ']':
self.pos += 1
return node
def test_solution():
root = Node(
val=1,
children=[Node(3, children=[Node(5), Node(6)]),
Node(2),
Node(4)])
coder = Codec()
ss = coder.encode(root)
# print(ss)
assert repr(coder.decode(ss)) == repr(root)
def decode(self, data):
"""Decodes your binary tree to an n-ary tree.
:type data: TreeNode
:rtype: Node
"""
if not data:
return None
rootNode = Node(data.val, [])
curr = data.left
while curr:
rootNode.children.append(self.decode(curr))
curr = curr.right
return rootNode
def connect(self, root: 'Node') -> 'Node':
"""
Good
https://leetcode-cn.com/problems/populating-next-right-pointers-in-each-node-ii/solution/xiang-xi-tong-su-de-si-lu-fen-xi-duo-jie-fa-by-28/
"""
if not root:
return root
cur = root
while cur:
dummy = Node(-1)
tail = dummy
# //遍历 cur 的当前层
while cur:
if cur.left:
tail.next = cur.left
tail = tail.next
if cur.right:
tail.next = cur.right
tail = tail.next
cur = cur.next
cur = dummy.next
# //更新 cur 到下一层
return root
"""
def cloneGraph(self, node: 'Node') -> 'Node':
if node is None:
return None
cloned_node = Node(node.val)
cloned_dict, queue = {node: cloned_node}, [node]
while queue:
current = queue.pop()
for neighbor in current.neighbors:
if neighbor not in cloned_dict:
queue.append(neighbor)
cloned_neighbor = Node(neighbor.val)
cloned_dict[neighbor] = cloned_neighbor
cloned_dict[current].neighbors.append(cloned_dict[neighbor])
return cloned_dict[node]
# leetcode submit region end(Prohibit modification and deletion)
@pytest.mark.parametrize("args,expected",
[(Node(val=12, neighbors=[Node(3), Node(4)]),
Node(val=12, neighbors=[Node(3), Node(4)]))])
def test_solutions(args, expected):
res = Solution().cloneGraph(args)
assert repr(res) == repr(expected)
if __name__ == '__main__':
pytest.main(["-q", "--color=yes", "--capture=no", __file__])
return root
class Solution2:
def connect(self, root: 'Node') -> 'Node':
"""
Good
"""
if not root: return root
if root.left:
root.left.next = root.right
if root.right and root.next:
root.right.next = root.next.left
self.connect(root.left)
self.connect(root.right)
return root
@pytest.mark.parametrize("args,expected", [[
Node(1, Node(2, Node(4), Node(5), None), Node(3, Node(6), Node(7), None),
None), [1, 2, 3, 4, 5, 6, 7]
]])
def test_solutions(args, expected):
assert repr(Solution().connect(copy.deepcopy(args))) == repr(expected)
assert repr(Solution1().connect(copy.deepcopy(args))) == repr(expected)
assert repr(Solution2().connect(copy.deepcopy(args))) == repr(expected)
if __name__ == '__main__':
pytest.main(["-q", "--color=yes", "--capture=no", __file__])
def test_solution():
p = Node(3, children=[Node(6)])
q = Node(8)
root = Node(1,
children=[
Node(2, children=[Node(4, children=[Node(7), q]),
Node(5)]), p
])
expected = Node(
1,
children=[
Node(2,
children=[
Node(4,
children=[
Node(7),
Node(8, children=[Node(3, children=[Node(6)])])
]),
Node(5)
])
])
res = Solution().moveSubTree(root, p, q)
assert repr(expected) == repr(res)
def helper():
root = Node(int(next(data)), [])
num = int(next(data))
for _ in range(num):
root.children.append(helper())
return root
class Solution:
def levelOrder(self, root: 'Node') -> List[List[int]]:
if not root: return []
results = []
q = deque([root])
level = 0
while q:
results.append([])
length = len(q)
for i in range(length):
node = q.popleft()
results[level].append(node.val)
if node.children:
q.extend(node.children)
level += 1
return results
@pytest.mark.parametrize("kw,expected", [
[
dict(root=Node(1, [Node(3, [Node(5), Node(
6)]), Node(2), Node(4)])), [[1], [3, 2, 4], [5, 6]]
],
])
def test_solutions(kw, expected):
assert Solution().levelOrder(**kw) == expected
if __name__ == '__main__':
pytest.main(["-q", "--color=yes", "--capture=no", __file__])
#
#
# 树的深度不会超过 1000。
# 树的节点总不会超过 5000。
# Related Topics 树 深度优先搜索 广度优先搜索
# 👍 98 👎 0
import pytest
from common_utils import TreeNodeWithChildren as Node
class Solution:
def maxDepth(self, root: 'Node') -> int:
if not root:
return 0
if not root.children:
return 1
return max([self.maxDepth(node) for node in root.children]) + 1
@pytest.mark.parametrize("kw,expected", [
[dict(root=Node(1, [Node(3, [Node(5), Node(6)]),
Node(2), Node(4)])), 3],
])
def test_solutions(kw, expected):
assert Solution().maxDepth(**kw) == expected
if __name__ == '__main__':
pytest.main(["-q", "--color=yes", "--capture=no", __file__])
class Solution:
def preorder(self, root: 'Node') -> List[int]:
if not root:
return []
results = []
stack = [root]
while stack:
cur = stack.pop()
results.append(cur.val)
children = cur.children
if children:
for child in children[::-1]:
stack.append(child)
return results
@pytest.mark.parametrize("kw,expected", [
[
dict(root=Node(1, [Node(3, [Node(5), Node(
6)]), Node(2), Node(4)])), [1, 3, 5, 6, 2, 4]
],
])
def test_solutions(kw, expected):
assert Solution().preorder(**kw) == expected
if __name__ == '__main__':
pytest.main(["-q", "--color=yes", "--capture=no", __file__])
current, prev, copies = head, dummy, {}
while current:
copied = Node(current.val)
copies[current] = copied
prev.next = copied
prev, current = prev.next, current.next
current = head
while current:
if current.random:
copies[current].random = copies[current.random]
current = current.next
return dummy.next
@pytest.mark.parametrize("args,expected", [[
Node.initList([[7, None], [13, 0], [11, 4], [10, 2], [1, 0]]),
Node.initList([[7, None], [13, 0], [11, 4], [10, 2], [1, 0]]),
]])
def test_solutions(args, expected):
res = Solution().copyRandomList(args)
cur_res = res
cur_expected = expected
while cur_res and cur_expected:
assert cur_res.val == cur_expected.val
if cur_res.random:
assert cur_res.random.val == cur_expected.random.val
cur_res, cur_expected = cur_res.next, cur_expected.next
assert cur_res is None and cur_expected is None
if __name__ == '__main__':
class Solution:
def postorder(self, root: 'Node') -> List[int]:
if not root:
return []
results = []
stack = [(root, False)]
while stack:
cur, is_visited = stack.pop()
if is_visited:
results.append(cur.val)
else:
stack.append((cur, True))
if cur.children:
for child in cur.children[::-1]:
stack.append((child, False))
return results
@pytest.mark.parametrize("args,expected", [[
Node(1, [Node(3, [Node(5), Node(6)]),
Node(2), Node(4)]), [5, 6, 3, 2, 4, 1]
], [None, []], [Node(1), [1]]])
def test_solutions(args, expected):
assert Solution().postorder(args) == expected
if __name__ == '__main__':
pytest.main(["-q", "--color=yes", "--capture=no", __file__])
def dfs(node):
max_dia = max_depth = 0
for child in node.children:
child_max_dia, child_max_depth = dfs(child)
max_dia = max(max_dia, child_max_dia,
max_depth + child_max_depth + 1)
max_depth = max(max_depth, child_max_depth + 1)
return max_dia, max_depth
return dfs(root)[0]
# leetcode submit region end(Prohibit modification and deletion)
@pytest.mark.parametrize("kwargs,expected", [
[
dict(root=Node(
1,
children=[Node(3, children=[Node(5), Node(6)]),
Node(2),
Node(4)])), 3
],
])
def test_solutions(kwargs, expected):
assert Solution().diameter(**kwargs) == expected
if __name__ == '__main__':
pytest.main(["-q", "--color=yes", "--capture=tee-sys", __file__])
class Solution1:
def connect(self, root: 'Node') -> 'Node':
if not root:
return root
queue = [root]
while queue:
size = len(queue)
for i in range(size - 1):
queue[i].next = queue[i + 1]
for i in range(size):
node = queue.pop(0)
if node.left:
queue.append(node.left)
if node.right:
queue.append(node.right)
return root
@pytest.mark.parametrize("args,expected", [
(Node(1, Node(2, None, Node(5), None), Node(3, None, Node(7), None), None),
[1, 2, 3, '#', 5, '#', 7])
])
@pytest.mark.parametrize("SolutionCLS", [Solution, Solution1])
def test_solutions(args, expected, SolutionCLS):
assert repr(SolutionCLS().connect(args)) == repr(expected)
if __name__ == '__main__':
pytest.main(["-q", "--color=yes", "--capture=no", __file__])