finish 01-homework

.gitignore

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+# Byte-compiled / optimized / DLL files
+__pycache__/
+*.py[cod]
+*$py.class
+
+# Distribution / packaging
+.Python
+env/
+build/
+dist/
+*.log
+
+# pyenv
+.python-version
+
+# dotenv
+.env
+
+# virtualenv
+.venv/
+venv/
+ENV/
+
+# VSCode settings
+.vscode
+
+# IDEA files
+.idea
+
+# OSX dir files
+.DS_Store
+
+# Sublime Text settings
+*.sublime-workspace
+*.sublime-project
+
+# History
+.history
+
+# test files
+homework_01_python/**/test/

homework_01_python/1-string/essay.txt

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+One is always on a strange road, watching strange scenery and listening to strange music. Then one day, you will find that the things you try hard to forget are already gone. 

homework_01_python/1-string/homework1.py

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+'''
+Author: SJ2050
+Date: 2021-10-10 23:22:04
+LastEditTime: 2021-10-10 23:34:06
+Version: v0.0.1
+Description: Solution for homework 1.
+Copyright © 2021 SJ2050
+'''
+
+if __name__ == '__main__':
+    with open('essay.txt', 'r') as fp_in:
+        content = fp_in.read()
+    word_map = {}
+    words = content.split()
+    for w in words:
+        if w in word_map:
+            word_map[w] += 1
+        else:
+            word_map[w] = 1
+
+    for (k, v) in word_map.items():
+        print(f'{k}: {v}')

homework_01_python/10-application3/homework10.py

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+'''
+Author: SJ2050
+Date: 2021-10-16 21:14:15
+LastEditTime: 2021-10-16 23:24:52
+Version: v0.0.1
+Description: Solution for homework10.
+Copyright © 2021 SJ2050
+'''
+import os
+
+if __name__ == '__main__':
+    res = {}
+    dir_path = './test/'
+    files= os.listdir(dir_path)
+
+    for file in files:
+        if not os.path.isdir(file):
+            ext = os.path.splitext(file)[-1][1:]
+            with open(dir_path+"/"+file) as fp:
+                count = len(fp.readlines())
+                if ext in res:
+                    res[ext] += count
+                else:
+                    res[ext] = count
+
+    print('统计结果如下: ')
+    for k, v in res.items():
+        print(f'{k}有: {v}行。')
+
+

homework_01_python/2-combination/homework2.py

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+'''
+Author: SJ2050
+Date: 2021-10-10 23:34:50
+LastEditTime: 2021-10-16 23:23:48
+Version: v0.0.1
+Description: Solution for homework 2.
+Copyright © 2021 SJ2050
+'''
+from itertools import permutations
+
+def combination(arr, n):
+    if n == 0:
+        return [[]]
+
+    l =[]
+    for i in range(0, len(arr)):
+        m = arr[i]
+        remLst = arr[i + 1:]
+
+        for p in combination(remLst, n-1):
+            l.append([m]+p)
+
+    return l
+
+
+def heapPermutation(arr, n, process):
+    if n == 1:
+        process(arr)
+        return
+
+    for i in range(n):
+        heapPermutation(arr, n-1, process)
+        if n & 1:
+            arr[0], arr[n-1] = arr[n-1], arr[0]
+        else:
+            arr[i], arr[n-1] = arr[n-1], arr[i]
+
+
+
+if __name__ == '__main__':
+    nums = [1, 2, 3, 4]
+    m = 3
+    count = 0
+    combs = combination(nums, m)
+
+    def printAndCount(arr):
+        global count
+        count += 1
+
+        for i in range(len(arr)):
+            print(f'{arr[i]}', end='')
+
+        print('')
+
+    print('3-digit nums:')
+    for c in combs:
+        heapPermutation(c, m, printAndCount)
+    print('-'*12)
+    print(f'Total count: {count}')
+
+    # 从一列数中取出三个元素组成三位数的算法复杂度分析:
+    # 首先是组合分析，从一列数中取出三个数的组合个数为n*(n-1)*(n-2)/6，算法时间复杂度为O(n^3).
+    # 接着，对每队组合进行排列，排列算法选用的是heap算法，其时间复杂度为O(n!).
+    # 故总的时间复杂度为: O((n^3)*(3!)) --> O(n^3)

homework_01_python/3-judgement/homework3.py

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+'''
+Author: SJ2050
+Date: 2021-10-16 22:24:48
+LastEditTime: 2021-10-16 22:44:04
+Version: v0.0.1
+Description: Solution for homework3.
+Copyright © 2021 SJ2050
+'''
+
+def judgement(x):
+    s = 0
+    p = 0
+
+    if x == 0:
+        return 0
+
+    if x <= 10:
+        s = 0
+        p = 0.1
+    elif x > 10 and x <= 20:
+        s = 10
+        p = 0.075
+    elif x > 20 and x <= 40:
+        s = 20
+        p = 0.05
+    elif x > 40 and x <= 60:
+        s = 40
+        p = 0.03
+    elif x > 60 and x <= 100:
+        s = 60
+        p = 0.015
+    else:
+        s = 100
+        p = 0.01
+
+    return (x-s)*p+judgement(s)
+
+import bisect
+
+# 使用列表来实现判断
+def judgementList(x):
+    a = [0, 10, 20, 40, 60, 100]
+    p = [0.1, 0.075, 0.05, 0.03, 0.015, 0.01]
+    ind = bisect.bisect_left(a, x)
+    res = 0
+
+    res += (x-a[ind-1])*p[ind-1]
+    for i in range(1, ind):
+        res += (a[i]-a[i-1])*(p[i-1])
+
+    return res
+
+
+if __name__ == '__main__':
+    x = 100
+    print(f'利润为:{x}w, 发放的奖金为{judgement(x)}w.')
+    print('----------------------------------------')
+    print('以下是使用列表计算的结果：')
+    print(f'利润为:{x}w, 发放的奖金为{judgementList(x)}w.')

homework_01_python/4-multiplication_table/homework4.py

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+'''
+Author: SJ2050
+Date: 2021-10-16 22:21:24
+LastEditTime: 2021-10-16 23:25:56
+Version: v0.0.1
+Description: Solution for homework4.
+Copyright © 2021 SJ2050
+'''
+
+if __name__ == '__main__':
+    for i in range(10):
+        for j in range (10-i,10):
+            print(f'{10-i}*{j}={(10-i)*j}', end='\t')
+        print('\n')
+
+    # 使用制表符来进行分割可以让乘法表格显示更加清楚

homework_01_python/5-while/homework5.py

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+'''
+Author: SJ2050
+Date: 2021-10-16 22:14:07
+LastEditTime: 2021-10-16 22:19:04
+Version: v0.0.1
+Description: Solution for homework5.
+Copyright © 2021 SJ2050
+'''
+
+if __name__ == '__main__':
+    i = 2
+    res = 0
+    while i <= 100:
+        res += (-1)**(i&1)*i
+        i += 1
+
+    print(f'result: {res}')
+
+    # 可以使用列表推导式一句话写完
+    res = sum([(-1)**(i&1)*i for i in range(2, 101)])
+
+    print(f'result: {res}')

homework_01_python/6-sort/homework6.py

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+'''
+Author: SJ2050
+Date: 2021-10-16 21:05:23
+LastEditTime: 2021-10-16 23:25:39
+Version: v0.0.1
+Description: Solution for homework6.
+Copyright © 2021 SJ2050
+'''
+
+def quickSort(lists, i, j):
+    if i >= j:
+        return list
+    pivot = lists[i]
+    low = i
+    high = j
+    while i < j:
+        while i < j and lists[j] <= pivot:
+            j -= 1
+        lists[i]=lists[j]
+        while i < j and lists[i] >= pivot:
+            i += 1
+        lists[j]=lists[i]
+    lists[j] = pivot
+    quickSort(lists,low,i-1)
+    quickSort(lists,i+1,high)
+    return lists
+
+
+if __name__ == '__main__':
+    # 采用快速排序法进行列表排序
+    lists = [1, 10, 4, 2, 9, 2, 34, 5, 9, 8, 5, 0]
+    ordered_lists = quickSort(lists, 0, len(lists)-1)
+    print('从大到小排列后的列表为: ')
+    print(ordered_lists)

homework_01_python/7-algorithm2/homework7.py

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+'''
+Author: SJ2050
+Date: 2021-10-16 22:04:07
+LastEditTime: 2021-10-16 23:25:30
+Version: v0.0.1
+Description: Solution for homework7.
+Copyright © 2021 SJ2050
+'''
+def searchMatrix(matrix, target):
+    if (len(matrix) == 0 ):
+        return False
+
+    i = len(matrix)-1
+    j = 0
+    while (i>=0 and j < len(matrix[0])):
+        if (matrix[i][j] == target):
+            return True
+        elif (matrix[i][j] < target):
+            j += 1
+        elif(matrix[i][j] > target):
+            i -= 1
+
+    return False
+
+if __name__ == "__main__":
+    matrix = [
+            [1, 4, 7, 11, 15],
+            [2, 5, 8, 12, 19],
+            [3, 6, 9, 16, 22],
+            [10, 13, 14, 17, 24],
+            [18, 21, 23, 26, 30]
+            ]
+    target = 20
+    print(searchMatrix(matrix, target))
+
+    # 算法说明：
+    # 从矩阵左下角，先排除不符合条件的列，再排除不符合条件的行，将范围一直往右上角缩小

homework_01_python/8-application1/homework8.py

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+'''
+Author: SJ2050
+Date: 2021-10-16 21:43:32
+LastEditTime: 2021-10-16 23:25:21
+Version: v0.0.1
+Description: Solution for homework8.
+Copyright © 2021 SJ2050
+'''
+import random
+import string
+
+def activationCode(count, length):
+    res = set()
+    base = string.ascii_letters + string.digits
+
+    while len(res) < count:
+        res.add(''.join(random.sample(base, length)))
+
+    return res
+
+if __name__ == '__main__':
+    n = 200  # count
+    l = 11   # length of each code
+
+    res = activationCode(n, l)
+    print(f'生成的{n}个激活码如下: ')
+    for item in res:
+        print(item)
+
+    # 激活码是用来授予用户相关权限的凭证，一般由一组数字和字母组成，其组合非常多，随机性较强，且能保证唯一，难以被外部破解。

homework_01_python/9-application2/homework9.py

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+'''
+Author: SJ2050
+Date: 2021-10-16 21:33:05
+LastEditTime: 2021-10-16 23:25:11
+Version: v0.0.1
+Description: Solution for homework9.
+Copyright © 2021 SJ2050
+'''
+from pathlib import Path
+
+if __name__ == '__main__':
+    dir_path = './test/'
+    print(sorted(Path('.').glob('**/*.dll')))