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Commit e7d4c4d

Browse files
author
hj.tian
committed
feat: add LeetCode75 day21 - day22
add LeetCode75 day21 - day22
1 parent cab17b8 commit e7d4c4d

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6 files changed

+122
-27
lines changed

6 files changed

+122
-27
lines changed

‎leetcode75/day21_110.py

Lines changed: 27 additions & 0 deletions
Original file line numberDiff line numberDiff line change
@@ -0,0 +1,27 @@
1+
from typing import Optional
2+
from helper import create_binary_tree, TreeNode
3+
4+
5+
class Solution:
6+
def isBalanced(self, root: Optional[TreeNode]) -> bool:
7+
if root is None:
8+
return True
9+
left_height = self.height(root.left)
10+
right_height = self.height(root.right)
11+
return abs(left_height - right_height) <= 1 and self.isBalanced(root.left) and self.isBalanced(root.right)
12+
13+
def height(self, root: Optional[TreeNode]) -> int:
14+
if root is None:
15+
return 0
16+
return max(self.height(root.left), self.height(root.right)) + 1
17+
18+
19+
if __name__ == "__main__":
20+
root = create_binary_tree([3, 9, 20, None, None, 15, 7], index=0)
21+
assert Solution().isBalanced(root) is True
22+
23+
root = create_binary_tree([1, 2, 2, 3, 3, None, None, 4, 4, None, None, None, None], index=0)
24+
assert Solution().isBalanced(root) is False
25+
26+
root = create_binary_tree([], index=0)
27+
assert Solution().isBalanced(root) is True

‎leetcode75/day21_226.py

Lines changed: 23 additions & 0 deletions
Original file line numberDiff line numberDiff line change
@@ -0,0 +1,23 @@
1+
from typing import Optional
2+
from helper import create_binary_tree, TreeNode, bfs_binary_tree
3+
4+
5+
class Solution:
6+
def invertTree(self, root: Optional[TreeNode]) -> Optional[TreeNode]:
7+
if root is None or (root.left is None and root.right is None):
8+
return root
9+
root.left, root.right = root.right, root.left
10+
self.invertTree(root.left)
11+
self.invertTree(root.right)
12+
return root
13+
14+
15+
if __name__ == "__main__":
16+
root = create_binary_tree([4, 2, 7, 1, 3, 6, 9], index=0)
17+
assert bfs_binary_tree(Solution().invertTree(root)) == [4, 7, 2, 9, 6, 3, 1]
18+
19+
root = create_binary_tree([2, 1, 3], index=0)
20+
assert bfs_binary_tree(Solution().invertTree(root)) == [2, 3, 1]
21+
22+
root = create_binary_tree([], index=0)
23+
assert bfs_binary_tree(Solution().invertTree(root)) == []

‎leetcode75/day22_543.py

Lines changed: 23 additions & 0 deletions
Original file line numberDiff line numberDiff line change
@@ -0,0 +1,23 @@
1+
from typing import Optional
2+
from helper import create_binary_tree, TreeNode
3+
4+
5+
class Solution:
6+
def diameterOfBinaryTree(self, root: Optional[TreeNode]) -> int:
7+
if root is None:
8+
return 0
9+
return max(
10+
self.height(root.left) + self.height(root.right),
11+
self.diameterOfBinaryTree(root.left),
12+
self.diameterOfBinaryTree(root.right),
13+
)
14+
15+
def height(self, root: Optional[TreeNode]) -> int:
16+
if root is None:
17+
return 0
18+
return max(self.height(root.left), self.height(root.right)) + 1
19+
20+
21+
if __name__ == "__main__":
22+
root = create_binary_tree([1, 2, 3, 4, 5, None, None], index=0)
23+
assert Solution().diameterOfBinaryTree(root) == 3

‎leetcode75/helper.py

Lines changed: 23 additions & 1 deletion
Original file line numberDiff line numberDiff line change
@@ -73,7 +73,7 @@ def __init__(self, val):
7373
self.right: Optional[TreeNode] = None
7474

7575

76-
def create_binary_tree(nums: List[int], index: int) -> Optional[TreeNode]:
76+
def create_binary_tree(nums: List[Optional[int]], index: int) -> Optional[TreeNode]:
7777
"""
7878
1
7979
2 2
@@ -87,3 +87,25 @@ def create_binary_tree(nums: List[int], index: int) -> Optional[TreeNode]:
8787
root.left = create_binary_tree(nums, index * 2 + 1)
8888
root.right = create_binary_tree(nums, index * 2 + 2)
8989
return root
90+
91+
92+
def bfs_binary_tree(root: Optional[TreeNode]) -> List[int]:
93+
# 层序遍历
94+
if root is None:
95+
return []
96+
queue = [root]
97+
results = []
98+
while queue:
99+
size = len(queue)
100+
nums = []
101+
next_queue = []
102+
for index in range(size):
103+
node = queue[index]
104+
nums.append(node.val if node else None)
105+
if node:
106+
next_queue.append(node.left)
107+
next_queue.append(node.right)
108+
if any(num is not None for num in nums):
109+
results.extend(nums)
110+
queue = next_queue
111+
return results

‎sword-means-offer/helper.py

Lines changed: 22 additions & 0 deletions
Original file line numberDiff line numberDiff line change
@@ -87,3 +87,25 @@ def create_binary_tree(nums: List[int], index: int) -> Optional[TreeNode]:
8787
root.left = create_binary_tree(nums, index * 2 + 1)
8888
root.right = create_binary_tree(nums, index * 2 + 2)
8989
return root
90+
91+
92+
def bfs_binary_tree(root: Optional[TreeNode]) -> List[int]:
93+
# 层序遍历
94+
if root is None:
95+
return []
96+
queue = [root]
97+
results = []
98+
while queue:
99+
size = len(queue)
100+
nums = []
101+
next_queue = []
102+
for index in range(size):
103+
node = queue[index]
104+
nums.append(node.val if node else None)
105+
if node:
106+
next_queue.append(node.left)
107+
next_queue.append(node.right)
108+
if any(num is not None for num in nums):
109+
results.extend(nums)
110+
queue = next_queue
111+
return results

‎sword-means-offer/offer_07.py

Lines changed: 4 additions & 26 deletions
Original file line numberDiff line numberDiff line change
@@ -1,27 +1,5 @@
11
from typing import List
2-
from helper import TreeNode
3-
4-
5-
def bfs(root: TreeNode) -> list:
6-
# 层序遍历
7-
if root is None:
8-
return []
9-
queue = [root]
10-
results = []
11-
while queue:
12-
size = len(queue)
13-
nums = []
14-
next_queue = []
15-
for index in range(size):
16-
node = queue[index]
17-
nums.append(node.val if node else None)
18-
if node:
19-
next_queue.append(node.left)
20-
next_queue.append(node.right)
21-
if any(num is not None for num in nums):
22-
results.extend(nums)
23-
queue = next_queue
24-
return results
2+
from helper import TreeNode, bfs_binary_tree
253

264

275
def preorder(root: TreeNode, nums) -> None:
@@ -108,10 +86,10 @@ def buildTree(self, preorder: List[int], inorder: List[int]) -> TreeNode:
10886

10987
assert nums == [9, 15, 7, 20, 3]
11088

111-
assert bfs(root) == [3, 9, 20, None, None, 15, 7]
89+
assert bfs_binary_tree(root) == [3, 9, 20, None, None, 15, 7]
11290

11391
root = s.buildTree([-1], [-1])
114-
assert bfs(root) == [-1]
92+
assert bfs_binary_tree(root) == [-1]
11593

11694
root = s.buildTree([], [])
117-
assert bfs(root) == []
95+
assert bfs_binary_tree(root) == []

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