Format python codes with black. (#453)

codes/python/chapter_array_and_linkedlist/array.py

@@ -6,6 +6,7 @@ Author: Krahets (krahets@163.com)
 
 import random
 
+
 def random_access(nums: list[int]) -> int:
     """随机访问元素"""
     # 在区间 [0, len(nums)-1] 中随机抽取一个数字
@@ -14,6 +15,7 @@ def random_access(nums: list[int]) -> int:
     random_num = nums[random_index]
     return random_num
 
+
 # 请注意，Python 的 list 是动态数组，可以直接扩展
 # 为了方便学习，本函数将 list 看作是长度不可变的数组
 def extend(nums: list[int], enlarge: int) -> list[int]:
@@ -26,6 +28,7 @@ def extend(nums: list[int], enlarge: int) -> list[int]:
     # 返回扩展后的新数组
     return res
 
+
 def insert(nums: list[int], num: int, index: int) -> None:
     """在数组的索引 index 处插入元素 num"""
     # 把索引 index 以及之后的所有元素向后移动一位
@@ -34,12 +37,14 @@ def insert(nums: list[int], num: int, index: int) -> None:
     # 将 num 赋给 index 处元素
     nums[index] = num
 
+
 def remove(nums: list[int], index: int) -> None:
     """删除索引 index 处元素"""
     # 把索引 index 之后的所有元素向前移动一位
     for i in range(index, len(nums) - 1):
         nums[i] = nums[i + 1]
 
+
 def traverse(nums: list[int]) -> None:
     """遍历数组"""
     count = 0
@@ -50,6 +55,7 @@ def traverse(nums: list[int]) -> None:
     for num in nums:
         count += 1
 
+
 def find(nums: list[int], target: int) -> int:
     """在数组中查找指定元素"""
     for i in range(len(nums)):
@@ -57,33 +63,34 @@ def find(nums: list[int], target: int) -> int:
             return i
     return -1
 
+
 """ Driver Code """
 if __name__ == "__main__":
-    """ 初始化数组 """
+    # 初始化数组
     arr: list[int] = [0] * 5
     print("数组 arr =", arr)
     nums: list[int] = [1, 3, 2, 5, 4]
     print("数组 nums =", nums)
 
-    """ 随机访问 """
+    # 随机访问
     random_num: int = random_access(nums)
     print("在 nums 中获取随机元素", random_num)
 
-    """ 长度扩展 """
+    # 长度扩展
     nums: list[int] = extend(nums, 3)
     print("将数组长度扩展至 8 ，得到 nums =", nums)
 
-    """ 插入元素 """
+    # 插入元素
     insert(nums, 6, 3)
     print("在索引 3 处插入数字 6 ，得到 nums =", nums)
 
-    """ 删除元素 """
+    # 删除元素
     remove(nums, 2)
     print("删除索引 2 处的元素，得到 nums =", nums)
 
-    """ 遍历数组 """
+    # 遍历数组
     traverse(nums)
 
-    """ 查找元素 """
+    # 查找元素
     index: int = find(nums, 3)
     print("在 nums 中查找元素 3 ，得到索引 =", index)

codes/python/chapter_array_and_linkedlist/linked_list.py

@@ -5,15 +5,18 @@ Author: Krahets (krahets@163.com)
 """
 
 import sys, os.path as osp
+
 sys.path.append(osp.dirname(osp.dirname(osp.abspath(__file__))))
 from modules import *
 
+
 def insert(n0: ListNode, P: ListNode) -> None:
     """在链表的节点 n0 之后插入节点 P"""
     n1 = n0.next
     P.next = n1
     n0.next = P
 
+
 def remove(n0: ListNode) -> None:
     """删除链表的节点 n0 之后的首个节点"""
     if not n0.next:
@@ -23,6 +26,7 @@ def remove(n0: ListNode) -> None:
     n1 = P.next
     n0.next = n1
 
+
 def access(head: ListNode, index: int) -> ListNode | None:
     """访问链表中索引为 index 的节点"""
     for _ in range(index):
@@ -31,6 +35,7 @@ def access(head: ListNode, index: int) -> ListNode | None:
         head = head.next
     return head
 
+
 def find(head: ListNode, target: int) -> int:
     """在链表中查找值为 target 的首个节点"""
     index = 0
@@ -44,7 +49,7 @@ def find(head: ListNode, target: int) -> int:
 
 """ Driver Code """
 if __name__ == "__main__":
-    """ 初始化链表 """
+    # 初始化链表
     # 初始化各个节点
     n0 = ListNode(1)
     n1 = ListNode(3)
@@ -59,20 +64,20 @@ if __name__ == "__main__":
     print("初始化的链表为")
     print_linked_list(n0)
 
-    """ 插入节点 """
+    # 插入节点
     insert(n0, ListNode(0))
     print("插入节点后的链表为")
     print_linked_list(n0)
 
-    """ 删除节点 """
+    # 删除节点
     remove(n0)
     print("删除节点后的链表为")
     print_linked_list(n0)
 
-    """ 访问节点 """
+    # 访问节点
     node: ListNode = access(n0, 3)
     print("链表中索引 3 处的节点的值 = {}".format(node.val))
 
-    """ 查找节点 """
+    # 查找节点
     index: int = find(n0, 2)
     print("链表中值为 2 的节点的索引 = {}".format(index))

codes/python/chapter_array_and_linkedlist/list.py

@@ -6,23 +6,23 @@ Author: Krahets (krahets@163.com)
 
 """ Driver Code """
 if __name__ == "__main__":
-    """ 初始化列表 """
+    # 初始化列表
     arr: list[int] = [1, 3, 2, 5, 4]
     print("列表 arr =", arr)
 
-    """ 访问元素 """
+    # 访问元素
     num: int = arr[1]
     print("访问索引 1 处的元素，得到 num =", num)
 
-    """ 更新元素 """
+    # 更新元素
     arr[1] = 0
     print("将索引 1 处的元素更新为 0 ，得到 arr =", arr)
 
-    """ 清空列表 """
+    # 清空列表
     arr.clear()
     print("清空列表后 arr =", arr)
 
-    """ 尾部添加元素 """
+    # 尾部添加元素
     arr.append(1)
     arr.append(3)
     arr.append(2)
@@ -30,29 +30,29 @@ if __name__ == "__main__":
     arr.append(4)
     print("添加元素后 arr =", arr)
 
-    """ 中间插入元素 """
+    # 中间插入元素
     arr.insert(3, 6)
     print("在索引 3 处插入数字 6 ，得到 arr =", arr)
 
-    """ 删除元素 """
+    # 删除元素
     arr.pop(3)
     print("删除索引 3 处的元素，得到 arr =", arr)
 
-    """ 通过索引遍历列表 """
+    # 通过索引遍历列表
     count: int = 0
     for i in range(len(arr)):
         count += 1
 
-    """ 直接遍历列表元素 """
+    # 直接遍历列表元素
     count: int = 0
     for n in arr:
         count += 1
 
-    """ 拼接两个列表 """
+    # 拼接两个列表
     arr1: list[int] = [6, 8, 7, 10, 9]
     arr += arr1
     print("将列表 arr1 拼接到 arr 之后，得到 arr =", arr)
 
-    """ 排序列表 """
+    # 排序列表
     arr.sort()
     print("排序列表后 arr =", arr)

codes/python/chapter_array_and_linkedlist/my_list.py

@@ -4,8 +4,10 @@ Created Time: 2022-11-25
 Author: Krahets (krahets@163.com)
 """
 
+
 class MyList:
     """列表类简易实现"""
+
     def __init__(self):
         """构造方法"""
         self.__capacity: int = 10  # 列表容量
@@ -79,36 +81,38 @@ class MyList:
 
 """ Driver Code """
 if __name__ == "__main__":
-    """ 初始化列表 """
+    # 初始化列表
     my_list = MyList()
-    """ 尾部添加元素 """
+    # 尾部添加元素
     my_list.add(1)
     my_list.add(3)
     my_list.add(2)
     my_list.add(5)
     my_list.add(4)
-    print("列表 my_list = {} ，容量 = {} ，长度 = {}"
+    print(
-          .format(my_list.to_array(), my_list.capacity(), my_list.size()))
+        f"列表 my_list = {my_list.to_array()} ，容量 = {my_list.capacity()} ，长度 = {my_list.size()}"
+    )
 
-    """ 中间插入元素 """
+    # 中间插入元素
     my_list.insert(6, index=3)
     print("在索引 3 处插入数字 6 ，得到 my_list =", my_list.to_array())
 
-    """ 删除元素 """
+    # 删除元素
     my_list.remove(3)
     print("删除索引 3 处的元素，得到 my_list =", my_list.to_array())
 
-    """ 访问元素 """
+    # 访问元素
     num = my_list.get(1)
     print("访问索引 1 处的元素，得到 num =", num)
 
-    """ 更新元素 """
+    # 更新元素
     my_list.set(0, 1)
     print("将索引 1 处的元素更新为 0 ，得到 my_list =", my_list.to_array())
 
-    """ 测试扩容机制 """
+    # 测试扩容机制
     for i in range(10):
         # 在 i = 5 时，列表长度将超出列表容量，此时触发扩容机制
         my_list.add(i)
-    print("扩容后的列表 my_list = {} ，容量 = {} ，长度 = {}"
+    print(
-          .format(my_list.to_array(), my_list.capacity(), my_list.size()))
+        "扩容后的列表 {my_list.to_array()} ，容量 = {my_list.capacity()} ，长度 = {my_list.size()}"
+    )

codes/python/chapter_computational_complexity/leetcode_two_sum.py

@@ -4,6 +4,7 @@ Created Time: 2022-11-25
 Author: Krahets (krahets@163.com)
 """
 
+
 def two_sum_brute_force(nums: list[int], target: int) -> list[int]:
     """方法一：暴力枚举"""
     # 两层循环，时间复杂度 O(n^2)
@@ -13,6 +14,7 @@ def two_sum_brute_force(nums: list[int], target: int) -> list[int]:
                 return [i, j]
     return []
 
+
 def two_sum_hash_table(nums: list[int], target: int) -> list[int]:
     """方法二：辅助哈希表"""
     # 辅助哈希表，空间复杂度 O(n)
@@ -26,7 +28,7 @@ def two_sum_hash_table(nums: list[int], target: int) -> list[int]:
 
 
 """ Driver Code """
-if __name__ == '__main__':
+if __name__ == "__main__":
     # ======= Test Case =======
     nums = [2, 7, 11, 15]
     target = 9

codes/python/chapter_computational_complexity/space_complexity.py

@@ -5,14 +5,17 @@ Author: Krahets (krahets@163.com)
 """
 
 import sys, os.path as osp
+
 sys.path.append(osp.dirname(osp.dirname(osp.abspath(__file__))))
 from modules import *
 
+
 def function() -> int:
     """函数"""
     # do something
     return 0
 
+
 def constant(n: int) -> None:
     """常数阶"""
     # 常量、变量、对象占用 O(1) 空间
@@ -26,6 +29,7 @@ def constant(n: int) -> None:
     for _ in range(n):
         function()
 
+
 def linear(n: int) -> None:
     """线性阶"""
     # 长度为 n 的列表占用 O(n) 空间
@@ -35,27 +39,34 @@ def linear(n: int) -> None:
     for i in range(n):
         mapp[i] = str(i)
 
+
 def linear_recur(n: int) -> None:
     """线性阶（递归实现）"""
     print("递归 n =", n)
-    if n == 1: return
+    if n == 1:
+        return
     linear_recur(n - 1)
 
+
 def quadratic(n: int) -> None:
     """平方阶"""
     # 二维列表占用 O(n^2) 空间
     num_matrix: list[list[int]] = [[0] * n for _ in range(n)]
 
+
 def quadratic_recur(n: int) -> int:
     """平方阶（递归实现）"""
-    if n <= 0: return 0
+    if n <= 0:
+        return 0
     # 数组 nums 长度为 n, n-1, ..., 2, 1
     nums: list[int] = [0] * n
     return quadratic_recur(n - 1)
 
+
 def build_tree(n: int) -> TreeNode | None:
     """指数阶（建立满二叉树）"""
-    if n == 0: return None
+    if n == 0:
+        return None
     root = TreeNode(0)
     root.left = build_tree(n - 1)
     root.right = build_tree(n - 1)

codes/python/chapter_computational_complexity/time_complexity.py

@@ -4,6 +4,7 @@ Created Time: 2022-11-25
 Author: Krahets (krahets@163.com)
 """
 
+
 def constant(n: int) -> int:
     """常数阶"""
     count: int = 0
@@ -12,6 +13,7 @@ def constant(n: int) -> int:
         count += 1
     return count
 
+
 def linear(n: int) -> int:
     """线性阶"""
     count: int = 0
@@ -19,6 +21,7 @@ def linear(n: int) -> int:
         count += 1
     return count
 
+
 def array_traversal(nums: list[int]) -> int:
     """线性阶（遍历数组）"""
     count: int = 0
@@ -27,6 +30,7 @@ def array_traversal(nums: list[int]) -> int:
         count += 1
     return count
 
+
 def quadratic(n: int) -> int:
     """平方阶"""
     count: int = 0
@@ -36,6 +40,7 @@ def quadratic(n: int) -> int:
             count += 1
     return count
 
+
 def bubble_sort(nums: list[int]) -> int:
     """平方阶（冒泡排序）"""
     count: int = 0  # 计数器
@@ -51,6 +56,7 @@ def bubble_sort(nums: list[int]) -> int:
                 count += 3  # 元素交换包含 3 个单元操作
     return count
 
+
 def exponential(n: int) -> int:
     """指数阶（循环实现）"""
     count: int = 0
@@ -63,11 +69,14 @@ def exponential(n: int) -> int:
     # count = 1 + 2 + 4 + 8 + .. + 2^(n-1) = 2^n - 1
     return count
 
+
 def exp_recur(n: int) -> int:
     """指数阶（递归实现）"""
-    if n == 1: return 1
+    if n == 1:
+        return 1
     return exp_recur(n - 1) + exp_recur(n - 1) + 1
 
+
 def logarithmic(n: float) -> int:
     """对数阶（循环实现）"""
     count: int = 0
@@ -76,23 +85,28 @@ def logarithmic(n: float) -> int:
         count += 1
     return count
 
+
 def log_recur(n: float) -> int:
     """对数阶（递归实现）"""
-    if n <= 1: return 0
+    if n <= 1:
+        return 0
     return log_recur(n / 2) + 1
 
+
 def linear_log_recur(n: float) -> int:
     """线性对数阶"""
-    if n <= 1: return 1
+    if n <= 1:
-    count: int = linear_log_recur(n // 2) + \
+        return 1
-                 linear_log_recur(n // 2)
+    count: int = linear_log_recur(n // 2) + linear_log_recur(n // 2)
     for _ in range(n):
         count += 1
     return count
 
+
 def factorial_recur(n: int) -> int:
     """阶乘阶（递归实现）"""
-    if n == 0: return 1
+    if n == 0:
+        return 1
     count: int = 0
     # 从 1 个分裂出 n 个
     for _ in range(n):

codes/python/chapter_computational_complexity/worst_best_time_complexity.py

@@ -6,6 +6,7 @@ Author: Krahets (krahets@163.com)
 
 import random
 
+
 def random_numbers(n: int) -> list[int]:
     """生成一个数组，元素为: 1, 2, ..., n ，顺序被打乱"""
     # 生成数组 nums =: 1, 2, 3, ..., n
@@ -14,6 +15,7 @@ def random_numbers(n: int) -> list[int]:
     random.shuffle(nums)
     return nums
 
+
 def find_one(nums: list[int]) -> int:
     """查找数组 nums 中数字 1 所在索引"""
     for i in range(len(nums)):

codes/python/chapter_graph/graph_adjacency_list.py

@@ -5,11 +5,14 @@ Author: Krahets (krahets@163.com)
 """
 
 import sys, os.path as osp
+
 sys.path.append(osp.dirname(osp.dirname(osp.abspath(__file__))))
 from modules import *
 
+
 class GraphAdjList:
     """基于邻接表实现的无向图类"""
+
     def __init__(self, edges: list[list[Vertex]]) -> None:
         """构造方法"""
         # 邻接表，key: 顶点，value：该顶点的所有邻接顶点
@@ -68,33 +71,39 @@ class GraphAdjList:
 
 """ Driver Code """
 if __name__ == "__main__":
-    """ 初始化无向图 """
+    # 初始化无向图
     v = vals_to_vets([1, 3, 2, 5, 4])
-    edges = [[v[0], v[1]], [v[0], v[3]], [v[1], v[2]],
+    edges = [
-             [v[2], v[3]], [v[2], v[4]], [v[3], v[4]]]
+        [v[0], v[1]],
+        [v[0], v[3]],
+        [v[1], v[2]],
+        [v[2], v[3]],
+        [v[2], v[4]],
+        [v[3], v[4]],
+    ]
     graph = GraphAdjList(edges)
     print("\n初始化后，图为")
     graph.print()
 
-    """ 添加边 """
+    # 添加边
     # 顶点 1, 2 即 v[0], v[2]
     graph.add_edge(v[0], v[2])
     print("\n添加边 1-2 后，图为")
     graph.print()
 
-    """ 删除边 """
+    # 删除边
     # 顶点 1, 3 即 v[0], v[1]
     graph.remove_edge(v[0], v[1])
     print("\n删除边 1-3 后，图为")
     graph.print()
 
-    """ 添加顶点 """
+    # 添加顶点
     v5 = Vertex(6)
     graph.add_vertex(v5)
     print("\n添加顶点 6 后，图为")
     graph.print()
 
-    """ 删除顶点 """
+    # 删除顶点
     # 顶点 3 即 v[1]
     graph.remove_vertex(v[1])
     print("\n删除顶点 3 后，图为")

codes/python/chapter_graph/graph_adjacency_matrix.py

@@ -5,11 +5,14 @@ Author: Krahets (krahets@163.com)
 """
 
 import sys, os.path as osp
+
 sys.path.append(osp.dirname(osp.dirname(osp.abspath(__file__))))
 from modules import *
 
+
 class GraphAdjMat:
     """基于邻接矩阵实现的无向图类"""
+
     # 顶点列表，元素代表“顶点值”，索引代表“顶点索引”
     vertices: list[int] = []
     # 邻接矩阵，行列索引对应“顶点索引”
@@ -83,7 +86,7 @@ class GraphAdjMat:
 
 """ Driver Code """
 if __name__ == "__main__":
-    """ 初始化无向图 """
+    # 初始化无向图
     # 请注意，edges 元素代表顶点索引，即对应 vertices 元素索引
     vertices: list[int] = [1, 3, 2, 5, 4]
     edges: list[list[int]] = [[0, 1], [0, 3], [1, 2], [2, 3], [2, 4], [3, 4]]
@@ -91,24 +94,24 @@ if __name__ == "__main__":
     print("\n初始化后，图为")
     graph.print()
 
-    """ 添加边 """
+    # 添加边
     # 顶点 1, 2 的索引分别为 0, 2
     graph.add_edge(0, 2)
     print("\n添加边 1-2 后，图为")
     graph.print()
 
-    """ 删除边 """
+    # 删除边
     # 顶点 1, 3 的索引分别为 0, 1
     graph.remove_edge(0, 1)
     print("\n删除边 1-3 后，图为")
     graph.print()
 
-    """ 添加顶点 """
+    # 添加顶点
     graph.add_vertex(6)
     print("\n添加顶点 6 后，图为")
     graph.print()
 
-    """ 删除顶点 """
+    # 删除顶点
     # 顶点 3 的索引为 1
     graph.remove_vertex(1)
     print("\n删除顶点 3 后，图为")

codes/python/chapter_graph/graph_bfs.py

@@ -5,11 +5,13 @@ Author: Krahets (krahets@163.com)
 """
 
 import sys, os.path as osp
+
 sys.path.append(osp.dirname(osp.dirname(osp.abspath(__file__))))
 from modules import *
 from collections import deque
 from graph_adjacency_list import GraphAdjList
 
+
 def graph_bfs(graph: GraphAdjList, start_vet: Vertex) -> list[Vertex]:
     """广度优先遍历 BFS"""
     # 使用邻接表来表示图，以便获取指定顶点的所有邻接顶点
@@ -35,16 +37,27 @@ def graph_bfs(graph: GraphAdjList, start_vet: Vertex) -> list[Vertex]:
 
 """ Driver Code """
 if __name__ == "__main__":
-    """初始化无向图"""
+    # 初始化无向图
     v = vals_to_vets([0, 1, 2, 3, 4, 5, 6, 7, 8, 9])
-    edges = [[v[0], v[1]], [v[0], v[3]], [v[1], v[2]], [v[1], v[4]],
+    edges = [
-             [v[2], v[5]], [v[3], v[4]], [v[3], v[6]], [v[4], v[5]],
+        [v[0], v[1]],
-             [v[4], v[7]], [v[5], v[8]], [v[6], v[7]], [v[7], v[8]]]
+        [v[0], v[3]],
+        [v[1], v[2]],
+        [v[1], v[4]],
+        [v[2], v[5]],
+        [v[3], v[4]],
+        [v[3], v[6]],
+        [v[4], v[5]],
+        [v[4], v[7]],
+        [v[5], v[8]],
+        [v[6], v[7]],
+        [v[7], v[8]],
+    ]
     graph = GraphAdjList(edges)
     print("\n初始化后，图为")
     graph.print()
 
-    """广度优先遍历 BFS"""
+    # 广度优先遍历 BFS
     res = graph_bfs(graph, v[0])
     print("\n广度优先遍历（BFS）顶点序列为")
     print(vets_to_vals(res))

codes/python/chapter_graph/graph_dfs.py

@@ -5,10 +5,12 @@ Author: Krahets (krahets@163.com)
 """
 
 import sys, os.path as osp
+
 sys.path.append(osp.dirname(osp.dirname(osp.abspath(__file__))))
 from modules import *
 from graph_adjacency_list import GraphAdjList
 
+
 def dfs(graph: GraphAdjList, visited: set[Vertex], res: list[Vertex], vet: Vertex):
     """深度优先遍历 DFS 辅助函数"""
     res.append(vet)  # 记录访问顶点
@@ -20,6 +22,7 @@ def dfs(graph: GraphAdjList, visited: set[Vertex], res: list[Vertex], vet: Verte
         # 递归访问邻接顶点
         dfs(graph, visited, res, adjVet)
 
+
 # 使用邻接表来表示图，以便获取指定顶点的所有邻接顶点
 def graph_dfs(graph: GraphAdjList, start_vet: Vertex) -> list[Vertex]:
     """深度优先遍历 DFS"""
@@ -35,8 +38,14 @@ def graph_dfs(graph: GraphAdjList, start_vet: Vertex) -> list[Vertex]:
 if __name__ == "__main__":
     # 初始化无向图
     v = vals_to_vets([0, 1, 2, 3, 4, 5, 6])
-    edges = [[v[0], v[1]], [v[0], v[3]], [v[1], v[2]], 
+    edges = [
-             [v[2], v[5]], [v[4], v[5]], [v[5], v[6]]]
+        [v[0], v[1]],
+        [v[0], v[3]],
+        [v[1], v[2]],
+        [v[2], v[5]],
+        [v[4], v[5]],
+        [v[5], v[6]],
+    ]
     graph = GraphAdjList(edges)
     print("\n初始化后，图为")
     graph.print()

codes/python/chapter_hashing/array_hash_map.py

@@ -4,14 +4,18 @@ Created Time: 2022-12-14
 Author: msk397 (machangxinq@gmail.com)
 """
 
+
 class Entry:
     """键值对 int->String"""
+
     def __init__(self, key: int, val: str):
         self.key = key
         self.val = val
 
+
 class ArrayHashMap:
     """基于数组简易实现的哈希表"""
+
     def __init__(self):
         """构造方法"""
         # 初始化数组，包含 100 个桶
@@ -75,10 +79,10 @@ class ArrayHashMap:
 
 """ Driver Code """
 if __name__ == "__main__":
-    """ 初始化哈希表 """
+    # 初始化哈希表
     mapp = ArrayHashMap()
 
-    """ 添加操作 """
+    # 添加操作
     # 在哈希表中添加键值对 (key, value)
     mapp.put(12836, "小哈")
     mapp.put(15937, "小啰")
@@ -88,18 +92,18 @@ if __name__ == "__main__":
     print("\n添加完成后，哈希表为\nKey -> Value")
     mapp.print()
 
-    """ 查询操作 """
+    # 查询操作
     # 向哈希表输入键 key ，得到值 value
     name = mapp.get(15937)
     print("\n输入学号 15937 ，查询到姓名 " + name)
 
-    """ 删除操作 """
+    # 删除操作
     # 在哈希表中删除键值对 (key, value)
     mapp.remove(10583)
     print("\n删除 10583 后，哈希表为\nKey -> Value")
     mapp.print()
 
-    """ 遍历哈希表 """
+    # 遍历哈希表
     print("\n遍历键值对 Key->Value")
     for pair in mapp.entry_set():
         print(pair.key, "->", pair.val)

codes/python/chapter_hashing/hash_map.py

@@ -5,15 +5,16 @@ Author: msk397 (machangxinq@gmail.com)
 """
 
 import sys, os.path as osp
+
 sys.path.append(osp.dirname(osp.dirname(osp.abspath(__file__))))
 from modules import *
 
 """ Driver Code """
 if __name__ == "__main__":
-    """ 初始化哈希表 """
+    # 初始化哈希表
     mapp = dict[int, str]()
 
-    """ 添加操作 """
+    # 添加操作
     # 在哈希表中添加键值对 (key, value)
     mapp[12836] = "小哈"
     mapp[15937] = "小啰"
@@ -23,18 +24,18 @@ if __name__ == "__main__":
     print("\n添加完成后，哈希表为\nKey -> Value")
     print_dict(mapp)
 
-    """ 查询操作 """
+    # 查询操作
     # 向哈希表输入键 key ，得到值 value
     name: str = mapp[15937]
     print("\n输入学号 15937 ，查询到姓名 " + name)
 
-    """ 删除操作 """
+    # 删除操作
     # 在哈希表中删除键值对 (key, value)
     mapp.pop(10583)
     print("\n删除 10583 后，哈希表为\nKey -> Value")
     print_dict(mapp)
 
-    """ 遍历哈希表 """
+    # 遍历哈希表
     print("\n遍历键值对 Key->Value")
     for key, value in mapp.items():
         print(key, "->", value)

codes/python/chapter_heap/heap.py

@@ -5,6 +5,7 @@ Author: Krahets (krahets@163.com)
 """
 
 import sys, os.path as osp
+
 sys.path.append(osp.dirname(osp.dirname(osp.abspath(__file__))))
 from modules import *
 
@@ -16,11 +17,13 @@ def test_push(heap: list, val: int, flag: int = 1) -> None:
     print(f"\n元素 {val} 入堆后")
     print_heap([flag * val for val in heap])
 
+
 def test_pop(heap: list, flag: int = 1) -> None:
     val = flag * heapq.heappop(heap)  # 堆顶元素出堆
     print(f"\n堆顶元素 {val} 出堆后")
     print_heap([flag * val for val in heap])
 
+
 """ Driver Code """
 if __name__ == "__main__":
     # 初始化小顶堆

codes/python/chapter_heap/my_heap.py

@@ -5,11 +5,14 @@ Author: Krahets (krahets@163.com)
 """
 
 import sys, os.path as osp
+
 sys.path.append(osp.dirname(osp.dirname(osp.abspath(__file__))))
 from modules import *
 
+
 class MaxHeap:
     """大顶堆"""
+
     def __init__(self, nums: list[int]):
         """构造方法"""
         # 将列表元素原封不动添加进堆

codes/python/chapter_searching/binary_search.py

@@ -4,6 +4,7 @@ Created Time: 2022-11-26
 Author: timi (xisunyy@163.com)
 """
 
+
 def binary_search(nums: list[int], target: int) -> int:
     """二分查找（双闭区间）"""
     # 初始化双闭区间 [0, n-1] ，即 i, j 分别指向数组首元素、尾元素
@@ -36,7 +37,7 @@ def binary_search1(nums: list[int], target: int) -> int:
 
 
 """ Driver Code """
-if __name__ == '__main__':
+if __name__ == "__main__":
     target: int = 6
     nums: list[int] = [1, 3, 6, 8, 12, 15, 23, 67, 70, 92]
 

codes/python/chapter_searching/hashing_search.py

@@ -5,16 +5,21 @@ Author: timi (xisunyy@163.com)
 """
 
 import sys, os.path as osp
+
 sys.path.append(osp.dirname(osp.dirname(osp.abspath(__file__))))
 from modules import *
 
+
 def hashing_search_array(mapp: dict[int, int], target: int) -> int:
     """哈希查找（数组）"""
     # 哈希表的 key: 目标元素，value: 索引
     # 若哈希表中无此 key ，返回 -1
     return mapp.get(target, -1)
 
-def hashing_search_linkedlist(mapp: dict[int, ListNode], target: int) -> ListNode | None:
+
+def hashing_search_linkedlist(
+    mapp: dict[int, ListNode], target: int
+) -> ListNode | None:
     """哈希查找（链表）"""
     # 哈希表的 key: 目标元素，value: 节点对象
     # 若哈希表中无此 key ，返回 None
@@ -22,7 +27,7 @@ def hashing_search_linkedlist(mapp: dict[int, ListNode], target: int) -> ListNod
 
 
 """ Driver Code """
-if __name__ == '__main__':
+if __name__ == "__main__":
     target: int = 3
 
     # 哈希查找（数组）

codes/python/chapter_searching/linear_search.py

@@ -5,9 +5,11 @@ Author: timi (xisunyy@163.com)
 """
 
 import sys, os.path as osp
+
 sys.path.append(osp.dirname(osp.dirname(osp.abspath(__file__))))
 from modules import *
 
+
 def linear_search_array(nums: list[int], target: int) -> int:
     """线性查找（数组）"""
     # 遍历数组
@@ -16,6 +18,7 @@ def linear_search_array(nums: list[int], target: int) -> int:
             return i
     return -1  # 未找到目标元素，返回 -1
 
+
 def linear_search_linkedlist(head: ListNode, target: int) -> ListNode | None:
     """线性查找（链表）"""
     # 遍历链表
@@ -27,7 +30,7 @@ def linear_search_linkedlist(head: ListNode, target: int) -> ListNode | None:
 
 
 """ Driver Code """
-if __name__ == '__main__':
+if __name__ == "__main__":
     target: int = 3
 
     # 在数组中执行线性查找

codes/python/chapter_sorting/bubble_sort.py

@@ -4,6 +4,7 @@ Created Time: 2022-11-25
 Author: timi (xisunyy@163.com)
 """
 
+
 def bubble_sort(nums: list[int]) -> None:
     """冒泡排序"""
     n: int = len(nums)
@@ -15,6 +16,7 @@ def bubble_sort(nums: list[int]) -> None:
                 # 交换 nums[j] 与 nums[j + 1]
                 nums[j], nums[j + 1] = nums[j + 1], nums[j]
 
+
 def bubble_sort_with_flag(nums: list[int]) -> None:
     """冒泡排序（标志优化）"""
     n: int = len(nums)
@@ -32,7 +34,7 @@ def bubble_sort_with_flag(nums: list[int]) -> None:
 
 
 """ Driver Code """
-if __name__ == '__main__':
+if __name__ == "__main__":
     nums: list[int] = [4, 1, 3, 1, 5, 2]
     bubble_sort(nums)
     print("排序后数组 nums =", nums)

codes/python/chapter_sorting/bucket_sort.py

@@ -4,6 +4,7 @@ Created Time: 2023-03-30
 Author: Krahets (krahets@163.com)
 """
 
+
 def bucket_sort(nums: list[float]) -> None:
     # 初始化 k = n/2 个桶，预期向每个桶分配 2 个元素
     k = len(nums) // 2
@@ -26,7 +27,7 @@ def bucket_sort(nums: list[float]) -> None:
             i += 1
 
 
-if __name__ == '__main__':
+if __name__ == "__main__":
     # 设输入数据为浮点数，范围为 [0, 1)
     nums = [0.49, 0.96, 0.82, 0.09, 0.57, 0.43, 0.91, 0.75, 0.15, 0.37]
     bucket_sort(nums)

codes/python/chapter_sorting/counting_sort.py

@@ -4,6 +4,7 @@ Created Time: 2023-03-21
 Author: Krahets (krahets@163.com)
 """
 
+
 def counting_sort_naive(nums: list[int]) -> None:
     """计数排序"""
     # 简单实现，无法用于排序对象
@@ -23,6 +24,7 @@ def counting_sort_naive(nums: list[int]) -> None:
             nums[i] = num
             i += 1
 
+
 def counting_sort(nums: list[int]) -> None:
     """计数排序"""
     # 完整实现，可排序对象，并且是稳定排序
@@ -49,6 +51,7 @@ def counting_sort(nums: list[int]) -> None:
     for i in range(n):
         nums[i] = res[i]
 
+
 """ Driver Code """
 if __name__ == "__main__":
     nums = [1, 0, 1, 2, 0, 4, 0, 2, 2, 4]

codes/python/chapter_sorting/insertion_sort.py

@@ -4,6 +4,7 @@ Created Time: 2022-11-25
 Author: timi (xisunyy@163.com)
 """
 
+
 def insertion_sort(nums: list[int]) -> None:
     """插入排序"""
     # 外循环：base = nums[1], nums[2], ..., nums[n-1]
@@ -18,7 +19,7 @@ def insertion_sort(nums: list[int]) -> None:
 
 
 """ Driver Code """
-if __name__ == '__main__':
+if __name__ == "__main__":
     nums: list[int] = [4, 1, 3, 1, 5, 2]
     insertion_sort(nums)
     print("排序后数组 nums =", nums)

codes/python/chapter_sorting/merge_sort.py

@@ -4,6 +4,7 @@ Created Time: 2022-11-25
 Author: timi (xisunyy@163.com)
 """
 
+
 def merge(nums: list[int], left: int, mid: int, right: int) -> None:
     """合并左子数组和右子数组"""
     # 左子数组区间 [left, mid]
@@ -34,6 +35,7 @@ def merge(nums: list[int], left: int, mid: int, right: int) -> None:
             nums[k] = tmp[j]
             j += 1
 
+
 def merge_sort(nums: list[int], left: int, right: int) -> None:
     """归并排序"""
     # 终止条件
@@ -48,7 +50,7 @@ def merge_sort(nums: list[int], left: int, right: int) -> None:
 
 
 """ Driver Code """
-if __name__ == '__main__':
+if __name__ == "__main__":
     nums: list[int] = [7, 3, 2, 6, 0, 1, 5, 4]
     merge_sort(nums, 0, len(nums) - 1)
     print("归并排序完成后 nums =", nums)

codes/python/chapter_sorting/quick_sort.py

@@ -4,8 +4,10 @@ Created Time: 2022-11-25
 Author: timi (xisunyy@163.com)
 """
 
+
 class QuickSort:
     """快速排序类"""
+
     def partition(self, nums: list[int], left: int, right: int) -> int:
         """哨兵划分"""
         # 以 nums[left] 作为基准数
@@ -32,8 +34,10 @@ class QuickSort:
         self.quick_sort(nums, left, pivot - 1)
         self.quick_sort(nums, pivot + 1, right)
 
+
 class QuickSortMedian:
     """快速排序类（中位基准数优化）"""
+
     def median_three(self, nums: list[int], left: int, mid: int, right: int) -> int:
         """选取三个元素的中位数"""
         # 此处使用异或运算来简化代码
@@ -74,8 +78,10 @@ class QuickSortMedian:
         self.quick_sort(nums, left, pivot - 1)
         self.quick_sort(nums, pivot + 1, right)
 
+
 class QuickSortTailCall:
     """快速排序类（尾递归优化）"""
+
     def partition(self, nums: list[int], left: int, right: int) -> int:
         """哨兵划分"""
         # 以 nums[left] 作为基准数
@@ -107,7 +113,7 @@ class QuickSortTailCall:
 
 
 """ Driver Code """
-if __name__ == '__main__':
+if __name__ == "__main__":
     # 快速排序
     nums: list[int] = [2, 4, 1, 0, 3, 5]
     QuickSort().quick_sort(nums, 0, len(nums) - 1)

codes/python/chapter_sorting/radix_sort.py

@@ -10,6 +10,7 @@ def digit(num: int, exp: int) -> int:
     # 传入 exp 而非 k 可以避免在此重复执行昂贵的次方计算
     return (num // exp) % 10
 
+
 def counting_sort_digit(nums: list[int], exp: int) -> None:
     """计数排序（根据 nums 第 k 位排序）"""
     # 十进制的位范围为 0~9 ，因此需要长度为 10 的桶
@@ -33,6 +34,7 @@ def counting_sort_digit(nums: list[int], exp: int) -> None:
     for i in range(n):
         nums[i] = res[i]
 
+
 def radix_sort(nums: list[int]) -> None:
     """基数排序"""
     # 获取数组的最大元素，用于判断最大位数
@@ -47,10 +49,21 @@ def radix_sort(nums: list[int]) -> None:
         counting_sort_digit(nums, exp)
         exp *= 10
 
+
 """ Driver Code """
-if __name__ == '__main__':
+if __name__ == "__main__":
     # 基数排序
-    nums = [10546151, 35663510, 42865989, 34862445, 81883077,
+    nums = [
-            88906420, 72429244, 30524779, 82060337, 63832996]
+        10546151,
+        35663510,
+        42865989,
+        34862445,
+        81883077,
+        88906420,
+        72429244,
+        30524779,
+        82060337,
+        63832996,
+    ]
     radix_sort(nums)
     print("基数排序完成后 nums =", nums)

codes/python/chapter_stack_and_queue/array_deque.py

@@ -4,8 +4,10 @@ Created Time: 2023-03-01
 Author: Krahets (krahets@163.com)
 """
 
+
 class ArrayDeque:
     """基于环形数组实现的双向队列"""
+
     def __init__(self, capacity: int) -> None:
         """构造方法"""
         self.__nums: list[int] = [0] * capacity
@@ -91,35 +93,35 @@ class ArrayDeque:
 
 """ Driver Code """
 if __name__ == "__main__":
-    """ 初始化双向队列 """
+    # 初始化双向队列
     deque = ArrayDeque(10)
     deque.push_last(3)
     deque.push_last(2)
     deque.push_last(5)
     print("双向队列 deque =", deque.to_array())
 
-    """ 访问元素 """
+    # 访问元素
     peek_first: int = deque.peek_first()
     print("队首元素 peek_first =", peek_first)
     peek_last: int = deque.peek_last()
     print("队尾元素 peek_last =", peek_last)
 
-    """ 元素入队 """
+    # 元素入队
     deque.push_last(4)
     print("元素 4 队尾入队后 deque =", deque.to_array())
     deque.push_first(1)
     print("元素 1 队首入队后 deque =", deque.to_array())
 
-    """ 元素出队 """
+    # 元素出队
     pop_last: int = deque.pop_last()
     print("队尾出队元素 =", pop_last, "，队尾出队后 deque =", deque.to_array())
     pop_first: int = deque.pop_first()
     print("队首出队元素 =", pop_first, "，队首出队后 deque =", deque.to_array())
 
-    """ 获取双向队列的长度 """
+    # 获取双向队列的长度
     size: int = deque.size()
     print("双向队列长度 size =", size)
 
-    """ 判断双向队列是否为空 """
+    # 判断双向队列是否为空
     is_empty: bool = deque.is_empty()
     print("双向队列是否为空 =", is_empty)

codes/python/chapter_stack_and_queue/array_queue.py

@@ -4,8 +4,10 @@ Created Time: 2022-12-01
 Author: Peng Chen (pengchzn@gmail.com)
 """
 
+
 class ArrayQueue:
     """基于环形数组实现的队列"""
+
     def __init__(self, size: int) -> None:
         """构造方法"""
         self.__nums: list[int] = [0] * size  # 用于存储队列元素的数组
@@ -59,10 +61,10 @@ class ArrayQueue:
 
 """ Driver Code """
 if __name__ == "__main__":
-    """ 初始化队列 """
+    # 初始化队列
     queue = ArrayQueue(10)
 
-    """ 元素入队 """
+    # 元素入队
     queue.push(1)
     queue.push(3)
     queue.push(2)
@@ -70,24 +72,24 @@ if __name__ == "__main__":
     queue.push(4)
     print("队列 queue =", queue.to_list())
 
-    """ 访问队首元素 """
+    # 访问队首元素
     peek: int = queue.peek()
     print("队首元素 peek =", peek)
 
-    """ 元素出队 """
+    # 元素出队
     pop: int = queue.pop()
     print("出队元素 pop =", pop)
     print("出队后 queue =", queue.to_list())
 
-    """ 获取队列的长度 """
+    # 获取队列的长度
     size: int = queue.size()
     print("队列长度 size =", size)
 
-    """ 判断队列是否为空 """
+    # 判断队列是否为空
     is_empty: bool = queue.is_empty()
     print("队列是否为空 =", is_empty)
 
-    """ 测试环形数组 """
+    # 测试环形数组
     for i in range(10):
         queue.push(i)
         queue.pop()

codes/python/chapter_stack_and_queue/array_stack.py

@@ -4,8 +4,10 @@ Created Time: 2022-11-29
 Author: Peng Chen (pengchzn@gmail.com)
 """
 
+
 class ArrayStack:
     """基于数组实现的栈"""
+
     def __init__(self) -> None:
         """构造方法"""
         self.__stack: list[int] = []
@@ -39,10 +41,10 @@ class ArrayStack:
 
 """ Driver Code """
 if __name__ == "__main__":
-    """ 初始化栈 """
+    # 初始化栈
     stack = ArrayStack()
 
-    """ 元素入栈 """
+    # 元素入栈
     stack.push(1)
     stack.push(3)
     stack.push(2)
@@ -50,19 +52,19 @@ if __name__ == "__main__":
     stack.push(4)
     print("栈 stack =", stack.to_list())
 
-    """ 访问栈顶元素 """
+    # 访问栈顶元素
     peek: int = stack.peek()
     print("栈顶元素 peek =", peek)
 
-    """ 元素出栈 """
+    # 元素出栈
     pop: int = stack.pop()
     print("出栈元素 pop =", pop)
     print("出栈后 stack =", stack.to_list())
 
-    """ 获取栈的长度 """
+    # 获取栈的长度
     size: int = stack.size()
     print("栈的长度 size =", size)
 
-    """ 判断是否为空 """
+    # 判断是否为空
     is_empty: bool = stack.is_empty()
     print("栈是否为空 =", is_empty)

codes/python/chapter_stack_and_queue/deque.py

@@ -8,10 +8,10 @@ from collections import deque
 
 """ Driver Code """
 if __name__ == "__main__":
-    """ 初始化双向队列 """
+    # 初始化双向队列
     deq: deque[int] = deque()
 
-    """ 元素入队 """
+    # 元素入队
     deq.append(2)  # 添加至队尾
     deq.append(5)
     deq.append(4)
@@ -19,13 +19,13 @@ if __name__ == "__main__":
     deq.appendleft(1)
     print("双向队列 deque =", deq)
 
-    """ 访问元素 """
+    # 访问元素
     front: int = deq[0]  # 队首元素
     print("队首元素 front =", front)
     rear: int = deq[-1]  # 队尾元素
     print("队尾元素 rear =", rear)
 
-    """ 元素出队 """
+    # 元素出队
     pop_front: int = deq.popleft()  # 队首元素出队
     print("队首出队元素  pop_front =", pop_front)
     print("队首出队后 deque =", deq)
@@ -33,10 +33,10 @@ if __name__ == "__main__":
     print("队尾出队元素  pop_rear =", pop_rear)
     print("队尾出队后 deque =", deq)
 
-    """ 获取双向队列的长度 """
+    # 获取双向队列的长度
     size: int = len(deq)
     print("双向队列长度 size =", size)
 
-    """ 判断双向队列是否为空 """
+    # 判断双向队列是否为空
     is_empty: bool = len(deq) == 0
     print("双向队列是否为空 =", is_empty)

codes/python/chapter_stack_and_queue/linkedlist_deque.py

@@ -4,16 +4,20 @@ Created Time: 2023-03-01
 Author: Krahets (krahets@163.com)
 """
 
+
 class ListNode:
     """双向链表节点"""
+
     def __init__(self, val: int) -> None:
         """构造方法"""
         self.val: int = val
         self.next: ListNode | None = None  # 后继节点引用（指针）
         self.prev: ListNode | None = None  # 前驱节点引用（指针）
 
+
 class LinkedListDeque:
     """基于双向链表实现的双向队列"""
+
     def __init__(self) -> None:
         """构造方法"""
         self.front: ListNode | None = None  # 头节点 front
@@ -110,35 +114,35 @@ class LinkedListDeque:
 
 """ Driver Code """
 if __name__ == "__main__":
-    """ 初始化双向队列 """
+    # 初始化双向队列
     deque = LinkedListDeque()
     deque.push_last(3)
     deque.push_last(2)
     deque.push_last(5)
     print("双向队列 deque =", deque.to_array())
 
-    """ 访问元素 """
+    # 访问元素
     peek_first: int = deque.peek_first()
     print("队首元素 peek_first =", peek_first)
     peek_last: int = deque.peek_last()
     print("队尾元素 peek_last =", peek_last)
 
-    """ 元素入队 """
+    # 元素入队
     deque.push_last(4)
     print("元素 4 队尾入队后 deque =", deque.to_array())
     deque.push_first(1)
     print("元素 1 队首入队后 deque =", deque.to_array())
 
-    """ 元素出队 """
+    # 元素出队
     pop_last: int = deque.pop_last()
     print("队尾出队元素 =", pop_last, "，队尾出队后 deque =", deque.to_array())
     pop_first: int = deque.pop_first()
     print("队首出队元素 =", pop_first, "，队首出队后 deque =", deque.to_array())
 
-    """ 获取双向队列的长度 """
+    # 获取双向队列的长度
     size: int = deque.size()
     print("双向队列长度 size =", size)
 
-    """ 判断双向队列是否为空 """
+    # 判断双向队列是否为空
     is_empty: bool = deque.is_empty()
     print("双向队列是否为空 =", is_empty)

codes/python/chapter_stack_and_queue/linkedlist_queue.py

@@ -5,11 +5,14 @@ Author: Peng Chen (pengchzn@gmail.com)
 """
 
 import sys, os.path as osp
+
 sys.path.append(osp.dirname(osp.dirname(osp.abspath(__file__))))
 from modules import *
 
+
 class LinkedListQueue:
     """基于链表实现的队列"""
+
     def __init__(self):
         """构造方法"""
         self.__front: ListNode | None = None  # 头节点 front
@@ -65,10 +68,10 @@ class LinkedListQueue:
 
 """ Driver Code """
 if __name__ == "__main__":
-    """ 初始化队列 """
+    # 初始化队列
     queue = LinkedListQueue()
 
-    """ 元素入队 """
+    # 元素入队
     queue.push(1)
     queue.push(3)
     queue.push(2)
@@ -76,19 +79,19 @@ if __name__ == "__main__":
     queue.push(4)
     print("队列 queue =", queue.to_list())
 
-    """ 访问队首元素 """
+    # 访问队首元素
     peek: int = queue.peek()
     print("队首元素 front =", peek)
 
-    """ 元素出队 """
+    # 元素出队
     pop_front: int = queue.pop()
     print("出队元素 pop =", pop_front)
     print("出队后 queue =", queue.to_list())
 
-    """ 获取队列的长度 """
+    # 获取队列的长度
     size: int = queue.size()
     print("队列长度 size =", size)
 
-    """ 判断队列是否为空 """
+    # 判断队列是否为空
     is_empty: bool = queue.is_empty()
     print("队列是否为空 =", is_empty)

codes/python/chapter_stack_and_queue/linkedlist_stack.py

@@ -5,11 +5,14 @@ Author: Peng Chen (pengchzn@gmail.com)
 """
 
 import sys, os.path as osp
+
 sys.path.append(osp.dirname(osp.dirname(osp.abspath(__file__))))
 from modules import *
 
+
 class LinkedListStack:
     """基于链表实现的栈"""
+
     def __init__(self):
         """构造方法"""
         self.__peek: ListNode | None = None
@@ -40,7 +43,8 @@ class LinkedListStack:
     def peek(self) -> int:
         """访问栈顶元素"""
         # 判空处理
-        if not self.__peek: return None
+        if not self.__peek:
+            return None
         return self.__peek.val
 
     def to_list(self) -> list[int]:
@@ -56,10 +60,10 @@ class LinkedListStack:
 
 """ Driver Code """
 if __name__ == "__main__":
-    """ 初始化栈 """
+    # 初始化栈
     stack = LinkedListStack()
 
-    """ 元素入栈 """
+    # 元素入栈
     stack.push(1)
     stack.push(3)
     stack.push(2)
@@ -67,19 +71,19 @@ if __name__ == "__main__":
     stack.push(4)
     print("栈 stack =", stack.to_list())
 
-    """ 访问栈顶元素 """
+    # 访问栈顶元素
     peek: int = stack.peek()
     print("栈顶元素 peek =", peek)
 
-    """ 元素出栈 """
+    # 元素出栈
     pop: int = stack.pop()
     print("出栈元素 pop =", pop)
     print("出栈后 stack =", stack.to_list())
 
-    """ 获取栈的长度 """
+    # 获取栈的长度
     size: int = stack.size()
     print("栈的长度 size =", size)
 
-    """ 判断是否为空 """
+    # 判断是否为空
     is_empty: bool = stack.is_empty()
     print("栈是否为空 =", is_empty)

codes/python/chapter_stack_and_queue/queue.py

@@ -8,13 +8,12 @@ from collections import deque
 
 """ Driver Code """
 if __name__ == "__main__":
-    
+    # 初始化队列
-    """ 初始化队列 """
     # 在 Python 中，我们一般将双向队列类 deque 看作队列使用
     # 虽然 queue.Queue() 是纯正的队列类，但不太好用
     que: deque[int] = deque()
 
-    """ 元素入队 """
+    # 元素入队
     que.append(1)
     que.append(3)
     que.append(2)
@@ -22,19 +21,19 @@ if __name__ == "__main__":
     que.append(4)
     print("队列 que =", que)
 
-    """ 访问队首元素 """
+    # 访问队首元素
     front: int = que[0]
     print("队首元素 front =", front)
 
-    """ 元素出队 """
+    # 元素出队
     pop: int = que.popleft()
     print("出队元素 pop =", pop)
     print("出队后 que =", que)
 
-    """ 获取队列的长度 """
+    # 获取队列的长度
     size: int = len(que)
     print("队列长度 size =", size)
 
-    """ 判断队列是否为空 """
+    # 判断队列是否为空
     is_empty: bool = len(que) == 0
     print("队列是否为空 =", is_empty)

codes/python/chapter_stack_and_queue/stack.py

@@ -6,11 +6,11 @@ Author: Peng Chen (pengchzn@gmail.com)
 
 """ Driver Code """
 if __name__ == "__main__":
-    """ 初始化栈 """
+    # 初始化栈
     # Python 没有内置的栈类，可以把 list 当作栈来使用
     stack: list[int] = []
 
-    """ 元素入栈 """
+    # 元素入栈
     stack.append(1)
     stack.append(3)
     stack.append(2)
@@ -18,19 +18,19 @@ if __name__ == "__main__":
     stack.append(4)
     print("栈 stack =", stack)
 
-    """ 访问栈顶元素 """
+    # 访问栈顶元素
     peek: int = stack[-1]
     print("栈顶元素 peek =", peek)
 
-    """ 元素出栈 """
+    # 元素出栈
     pop: int = stack.pop()
     print("出栈元素 pop =", pop)
     print("出栈后 stack =", stack)
 
-    """ 获取栈的长度 """
+    # 获取栈的长度
     size: int = len(stack)
     print("栈的长度 size =", size)
 
-    """ 判断是否为空 """
+    # 判断是否为空
     is_empty: bool = len(stack) == 0
     print("栈是否为空 =", is_empty)

codes/python/chapter_tree/avl_tree.py

@@ -5,11 +5,14 @@ Author: a16su (lpluls001@gmail.com)
 """
 
 import sys, os.path as osp
+
 sys.path.append(osp.dirname(osp.dirname(osp.abspath(__file__))))
 from modules import *
 
+
 class AVLTree:
     """AVL 树"""
+
     def __init__(self, root: TreeNode | None = None):
         """构造方法"""
         self.__root = root
@@ -172,6 +175,7 @@ class AVLTree:
 
 """ Driver Code """
 if __name__ == "__main__":
+
     def test_insert(tree: AVLTree, val: int):
         tree.insert(val)
         print("\n插入节点 {} 后，AVL 树为".format(val))

codes/python/chapter_tree/binary_search_tree.py

@@ -5,18 +5,22 @@ Author: a16su (lpluls001@gmail.com)
 """
 
 import sys, os.path as osp
+
 sys.path.append(osp.dirname(osp.dirname(osp.abspath(__file__))))
 from modules import *
 
 
 class BinarySearchTree:
     """二叉搜索树"""
+
     def __init__(self, nums: list[int]) -> None:
         """构造方法"""
         nums.sort()
         self.__root = self.build_tree(nums, 0, len(nums) - 1)
 
-    def build_tree(self, nums: list[int], start_index: int, end_index: int) -> TreeNode | None:
+    def build_tree(
+        self, nums: list[int], start_index: int, end_index: int
+    ) -> TreeNode | None:
         """构建二叉搜索树"""
         if start_index > end_index:
             return None
@@ -25,8 +29,12 @@ class BinarySearchTree:
         mid: int = (start_index + end_index) // 2
         root = TreeNode(nums[mid])
         # 递归建立左子树和右子树
-        root.left = self.build_tree(nums=nums, start_index=start_index, end_index=mid - 1)
+        root.left = self.build_tree(
-        root.right = self.build_tree(nums=nums, start_index=mid + 1, end_index=end_index)
+            nums=nums, start_index=start_index, end_index=mid - 1
+        )
+        root.right = self.build_tree(
+            nums=nums, start_index=mid + 1, end_index=end_index
+        )
         return root
 
     @property

codes/python/chapter_tree/binary_tree.py

@@ -12,7 +12,7 @@ from modules import *
 
 """ Driver Code """
 if __name__ == "__main__":
-    """ 初始化二叉树 """
+    # 初始化二叉树
     # 初始化节点
     n1 = TreeNode(val=1)
     n2 = TreeNode(val=2)
@@ -27,7 +27,7 @@ if __name__ == "__main__":
     print("\n初始化二叉树\n")
     print_tree(n1)
 
-    """ 插入与删除节点 """
+    # 插入与删除节点
     P = TreeNode(0)
     # 在 n1 -> n2 中间插入节点 P
     n1.left = P

codes/python/chapter_tree/binary_tree_bfs.py

@@ -5,10 +5,12 @@ Author: a16su (lpluls001@gmail.com)
 """
 
 import sys, os.path as osp
+
 sys.path.append(osp.dirname(osp.dirname(osp.abspath(__file__))))
 from modules import *
 from collections import deque
 
+
 def level_order(root: TreeNode | None) -> list[int]:
     """层序遍历"""
     # 初始化队列，加入根节点

codes/python/chapter_tree/binary_tree_dfs.py

@@ -5,9 +5,11 @@ Author: a16su (lpluls001@gmail.com)
 """
 
 import sys, os.path as osp
+
 sys.path.append(osp.dirname(osp.dirname(osp.abspath(__file__))))
 from modules import *
 
+
 def pre_order(root: TreeNode | None) -> None:
     """前序遍历"""
     if root is None:
@@ -17,6 +19,7 @@ def pre_order(root: TreeNode | None) -> None:
     pre_order(root=root.left)
     pre_order(root=root.right)
 
+
 def in_order(root: TreeNode | None) -> None:
     """中序遍历"""
     if root is None:
@@ -26,6 +29,7 @@ def in_order(root: TreeNode | None) -> None:
     res.append(root.val)
     in_order(root=root.right)
 
+
 def post_order(root: TreeNode | None) -> None:
     """后序遍历"""
     if root is None:

codes/python/modules/__init__.py

@@ -1,8 +1,20 @@
 # Follow the PEP 585 – Type Hinting Generics In Standard Collections
 # https://peps.python.org/pep-0585/
 from __future__ import annotations
+
 # Import common libs here to simplify the codes by `from module import *`
-from .linked_list import ListNode, list_to_linked_list, linked_list_to_list, get_list_node
+from .linked_list import (
+    ListNode,
+    list_to_linked_list,
+    linked_list_to_list,
+    get_list_node,
+)
 from .binary_tree import TreeNode, list_to_tree, tree_to_list, get_tree_node
 from .vertex import Vertex, vals_to_vets, vets_to_vals
-from .print_util import print_matrix, print_linked_list, print_tree, print_dict, print_heap
+from .print_util import (
+    print_matrix,
+    print_linked_list,
+    print_tree,
+    print_dict,
+    print_heap,
+)

codes/python/modules/binary_tree.py

@@ -6,14 +6,17 @@ Author: Krahets (krahets@163.com)
 
 from collections import deque
 
+
 class TreeNode:
     """Definition for a binary tree node"""
+
     def __init__(self, val: int = 0):
         self.val: int = val  # 节点值
         self.height: int = 0  # 节点高度
         self.left: TreeNode | None = None  # 左子节点引用
         self.right: TreeNode | None = None  # 右子节点引用
 
+
 def list_to_tree(arr: list[int]) -> TreeNode | None:
     """Generate a binary tree with a list"""
     if not arr:
@@ -25,21 +28,25 @@ def list_to_tree(arr: list[int]) -> TreeNode | None:
     while queue:
         node: TreeNode = queue.popleft()
         i += 1
-        if i >= len(arr): break
+        if i >= len(arr):
+            break
         if arr[i] != None:
             node.left = TreeNode(arr[i])
             queue.append(node.left)
         i += 1
-        if i >= len(arr): break
+        if i >= len(arr):
+            break
         if arr[i] != None:
             node.right = TreeNode(arr[i])
             queue.append(node.right)
 
     return root
 
+
 def tree_to_list(root: TreeNode | None) -> list[int]:
     """Serialize a tree into an array"""
-    if not root: return []
+    if not root:
+        return []
     queue: deque[TreeNode] = deque()
     queue.append(root)
     res: list[int] = []
@@ -49,9 +56,11 @@ def tree_to_list(root: TreeNode | None) -> list[int]:
             res.append(node.val)
             queue.append(node.left)
             queue.append(node.right)
-        else: res.append(None)
+        else:
+            res.append(None)
     return res
 
+
 def get_tree_node(root: TreeNode | None, val: int) -> TreeNode | None:
     """Get a tree node with specific value in a binary tree"""
     if not root:

codes/python/modules/linked_list.py

@@ -4,12 +4,15 @@ Created Time: 2021-12-11
 Author: Krahets (krahets@163.com)
 """
 
+
 class ListNode:
     """Definition for a singly-linked list node"""
+
     def __init__(self, val: int):
         self.val: int = val  # 节点值
         self.next: ListNode | None = None  # 后继节点引用
 
+
 def list_to_linked_list(arr: list[int]) -> ListNode | None:
     """Generate a linked list with a list"""
     dum = head = ListNode(0)
@@ -19,6 +22,7 @@ def list_to_linked_list(arr: list[int]) -> ListNode | None:
         head = head.next
     return dum.next
 
+
 def linked_list_to_list(head: ListNode | None) -> list[int]:
     """Serialize a linked list into an array"""
     arr: list[int] = []
@@ -27,6 +31,7 @@ def linked_list_to_list(head: ListNode | None) -> list[int]:
         head = head.next
     return arr
 
+
 def get_list_node(head: ListNode | None, val: int) -> ListNode | None:
     """Get a list node with specific value from a linked list"""
     while head and head.val != val:

codes/python/modules/print_util.py

@@ -7,31 +7,38 @@ Author: Krahets (krahets@163.com), msk397 (machangxinq@gmail.com)
 from .binary_tree import TreeNode, list_to_tree
 from .linked_list import ListNode, linked_list_to_list
 
+
 def print_matrix(mat: list[list[int]]) -> None:
     """Print a matrix"""
     s: list[str] = []
     for arr in mat:
-        s.append('  ' + str(arr))
+        s.append("  " + str(arr))
+
+    print("[\n" + ",\n".join(s) + "\n]")
 
-    print('[\n' + ',\n'.join(s) + '\n]')
 
 def print_linked_list(head: ListNode | None) -> None:
     """Print a linked list"""
     arr: list[int] = linked_list_to_list(head)
-    print(' -> '.join([str(a) for a in arr]))
+    print(" -> ".join([str(a) for a in arr]))
+
 
 class Trunk:
     def __init__(self, prev, string: str | None = None) -> None:
         self.prev = prev
         self.str = string
 
+
 def show_trunks(p: Trunk | None) -> None:
     if p is None:
         return
     show_trunks(p.prev)
-    print(p.str, end='')
+    print(p.str, end="")
 
-def print_tree(root: TreeNode | None, prev: Trunk | None = None, is_left: bool = False) -> None:
+
+def print_tree(
+    root: TreeNode | None, prev: Trunk | None = None, is_left: bool = False
+) -> None:
     """
     Print a binary tree
     This tree printer is borrowed from TECHIE DELIGHT
@@ -40,30 +47,32 @@ def print_tree(root: TreeNode | None, prev: Trunk | None = None, is_left: bool =
     if root is None:
         return
 
-    prev_str: str = '    '
+    prev_str: str = "    "
     trunk = Trunk(prev, prev_str)
     print_tree(root.right, trunk, True)
 
     if prev is None:
-        trunk.str = '———'
+        trunk.str = "———"
     elif is_left:
-        trunk.str = '/———'
+        trunk.str = "/———"
-        prev_str = '   |'
+        prev_str = "   |"
     else:
-        trunk.str = '\———'
+        trunk.str = "\———"
         prev.str = prev_str
 
     show_trunks(trunk)
-    print(' ' + str(root.val))
+    print(" " + str(root.val))
     if prev:
         prev.str = prev_str
-    trunk.str = '   |'
+    trunk.str = "   |"
     print_tree(root.left, trunk, False)
 
+
 def print_dict(mapp: dict) -> None:
     """Print a dict"""
     for key, value in mapp.items():
-        print(key, '->', value)
+        print(key, "->", value)
+
 
 def print_heap(heap: list[int]) -> None:
     """Print a heap both in array and tree representations"""

codes/python/modules/vertex.py

@@ -2,15 +2,19 @@
 # Created Time: 2023-02-23
 # Author: Krahets (krahets@163.com)
 
+
 class Vertex:
     """顶点类"""
+
     def __init__(self, val: int) -> None:
         self.val = val
 
-def vals_to_vets(vals: list[int]) -> list['Vertex']:
+
+def vals_to_vets(vals: list[int]) -> list["Vertex"]:
     """输入值列表 vals ，返回顶点列表 vets"""
     return [Vertex(val) for val in vals]
 
-def vets_to_vals(vets: list['Vertex']) -> list[int]:
+
+def vets_to_vals(vets: list["Vertex"]) -> list[int]:
     """输入顶点列表 vets ，返回值列表 vals"""
     return [vet.val for vet in vets]