Hw8

task_1.py

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+# 2. Закодируйте любую строку из трех слов по алгоритму Хаффмана.
+import collections
+
+
+class HaffNode:
+    def __init__(self, value=None, left=None, right=None):
+        self.value = value
+        self.left = left
+        self.right = right
+
+        if type(self.left) is HaffNode:
+            self.left.num = 0
+            self.left.parent = self
+        if type(self.right) is HaffNode:
+            self.right.num = 1
+            self.right.parent = self
+
+    def get_code_dict(self, code_dict, path=''):
+        if self.value is not None:
+            code_dict[self.value] = path
+        else:
+            if self.left is not None:
+                self.left.get_code_dict(code_dict, f'{path}0')
+            if self.right is not None:
+                self.right.get_code_dict(code_dict, f'{path}1')
+
+    def __repr__(self):
+        if self.value:
+            return f'--{self.value}--'
+        return f'{self.left}  {self.right}\n'
+
+
+def haffman(string):
+    array = []
+    array.extend(string)
+    lst = collections.Counter(array)
+    lst = collections.deque(lst.most_common(len(lst))[::-1])
+    print(lst)
+    for i in range(len(lst)):
+        lst[i] = HaffNode(value=lst[i][0]), lst[i][1]
+    # print(lst)
+
+    while len(lst) > 1:
+
+        lst[1] = (HaffNode(left=lst[0][0], right=lst[1][0]), lst[0][1] + lst[1][1])
+        lst.popleft()
+
+        for i in range(len(lst) - 1):
+            if lst[i][1] > lst[i + 1][1]:
+                lst[i], lst[i + 1] = lst[i + 1], lst[i]
+            else:
+                break
+    code_dict = dict()
+    lst[0][0].get_code_dict(code_dict)
+    print(code_dict)
+
+    arch = ''
+    for i in range(len(array)):
+        # print(f'{code_dict[array[i]]} ', end='')
+        arch += code_dict[array[i]]
+    # print()
+    return (arch, code_dict)
+
+
+def dehaffman(string, code_dict):
+    code_dict = {v: k for k, v in code_dict.items()}
+    i = 0
+    len_ = 2
+    dearch = ''
+    while i < len(string):
+        find_str = string[i:i + len_]
+        if find_str in code_dict:
+            dearch += code_dict[find_str]
+            i += len_
+            len_ = 2
+        else:
+            len_ += 1
+
+    return dearch
+
+
+check_string = 'Проверка алгоритма Хаффмана'
+print(check_string)
+arch, code_dict = haffman(check_string)
+print(arch)
+print(dehaffman(arch, code_dict))