Merge pull request #2 from 2022WPJ/master

Add solutions

CH_04_design_patterns/exercise_03/solution_01.py

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+class Borg:
+
+    def __new__(cls):
+        if not hasattr(cls, '_state'):
+            cls._state = {}
+        instance = super(Borg, cls).__new__(cls)
+        instance.__dict__ = cls._state
+        return instance
+
+
+class SubBorg(Borg):
+    pass
+
+
+class SubBorg2(Borg):
+    pass
+
+
+def main():
+    a = SubBorg()
+    b = SubBorg()
+    c = SubBorg2()
+    a.attr = 10
+    assert hasattr(b, 'attr') and b.attr == 10
+    assert not hasattr(c, 'attr')
+
+
+if __name__ == '__main__':
+    main()

CH_05_functional_programming/exercise_01/solution_01.py

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+import random
+
+
+def quicksort(nums, left=None, right=None):
+    if left is None:
+        left = 0
+    if right is None:
+        right = len(nums) - 1
+    if right <= left:
+        return
+    j = left
+    temp = nums[right]
+    for i in range(left, right):
+        if nums[i] < temp:
+            nums[i], nums[j] = nums[j], nums[i]
+            j += 1
+    nums[j], nums[right] = nums[right], nums[j]
+    quicksort(nums, left, j - 1)
+    quicksort(nums, j + 1, right)
+    return nums
+
+
+def main():
+    nums = random.sample(range(100000), 100000)
+    assert sorted(nums) == quicksort(nums)
+
+
+if __name__ == '__main__':
+    main()