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Update Python codes.

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This commit is contained in:
krahets 2023-02-06 04:11:22 +08:00
parent 4655534bd6
commit 1b0a3a6e69
4 changed files with 10 additions and 8 deletions
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3
codes/python/chapter_computational_complexity/leetcode_two_sum.py
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@ -11,6 +11,7 @@ from include import *
""" 方法一：暴力枚举 """ """ 方法一：暴力枚举 """
class SolutionBruteForce: class SolutionBruteForce:
def twoSum(self, nums: List[int], target: int) -> List[int]: def twoSum(self, nums: List[int], target: int) -> List[int]:
# 两层循环，时间复杂度 O(n^2)
for i in range(len(nums) - 1): for i in range(len(nums) - 1):
for j in range(i + 1, len(nums)): for j in range(i + 1, len(nums)):
if nums[i] + nums[j] == target: if nums[i] + nums[j] == target:
@ -20,7 +21,9 @@ class SolutionBruteForce:
""" 方法二：辅助哈希表 """ """ 方法二：辅助哈希表 """
class SolutionHashMap: class SolutionHashMap:
def twoSum(self, nums: List[int], target: int) -> List[int]: def twoSum(self, nums: List[int], target: int) -> List[int]:
# 辅助哈希表，空间复杂度 O(n)
dic = {} dic = {}
# 单层循环，时间复杂度 O(n)
for i in range(len(nums)): for i in range(len(nums)):
if target - nums[i] in dic: if target - nums[i] in dic:
return dic[target - nums[i]], i return dic[target - nums[i]], i

4
codes/python/chapter_computational_complexity/space_complexity.py
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@ -21,7 +21,7 @@ def constant(n):
node = ListNode(0) node = ListNode(0)
# 循环中的变量占用 O(1) 空间 # 循环中的变量占用 O(1) 空间
for _ in range(n): for _ in range(n):
c = 0 c = 0
# 循环中的函数占用 O(1) 空间 # 循环中的函数占用 O(1) 空间
for _ in range(n): for _ in range(n):
function() function()
@ -49,8 +49,8 @@ def quadratic(n):
""" 平方阶（递归实现） """ """ 平方阶（递归实现） """
def quadratic_recur(n): def quadratic_recur(n):
if n <= 0: return 0 if n <= 0: return 0
# 数组 nums 长度为 n, n-1, ..., 2, 1
nums = [0] * n nums = [0] * n
print("递归 n =", n, "中的 nums 长度 =", len(nums))
return quadratic_recur(n - 1) return quadratic_recur(n - 1)
""" 指数阶（建立满二叉树） """ """ 指数阶（建立满二叉树） """

9
codes/python/chapter_sorting/merge_sort.py
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@ -8,11 +8,10 @@ import sys, os.path as osp
sys.path.append(osp.dirname(osp.dirname(osp.abspath(__file__)))) sys.path.append(osp.dirname(osp.dirname(osp.abspath(__file__))))
from include import * from include import *
"""
合并左子数组和右子数组 """ 合并左子数组和右子数组 """
左子数组区间 [left, mid] # 左子数组区间 [left, mid]
右子数组区间 [mid + 1, right] # 右子数组区间 [mid + 1, right]
"""
def merge(nums, left, mid, right): def merge(nums, left, mid, right):
# 初始化辅助数组 借助 copy模块 # 初始化辅助数组 借助 copy模块
tmp = nums[left:right + 1] tmp = nums[left:right + 1]