Домашнее задание №8

Урок 8. Практическое задание/task_1.py

@@ -16,3 +16,19 @@
 
 Итог: 6 подстрок
 """
+from hashlib import sha1
+
+STR = 'Python3'
+my_set = set()
+
+for first_sym in range(len(STR)):
+    if first_sym == 0:
+        length_sym = len(STR) - 1
+    else:
+        length_sym = len(STR)
+    for last_sym in range(length_sym):
+        if last_sym >= first_sym:
+            substring = sha1(STR[first_sym:last_sym + 1].encode('utf-8')).hexdigest()
+            my_set.add(substring)
+
+print(f'В строке - {STR} - {len(my_set)} подстрок')

Урок 8. Практическое задание/task_2.py

@@ -8,3 +8,49 @@
 Результат:
 00 11 11 101 010 00 011 011 101 010 00 11 11 1000 1001
 """
+
+from collections import Counter, deque
+
+S = "beep boop beer!"
+# S = "bbbbbbb"
+
+
+def haffman_tree(string):
+    cnt = Counter(string)
+    sort_cnt = deque(sorted(cnt.items(), key=lambda x: x[1]))
+    if len(sort_cnt) > 1:
+        while len(sort_cnt) > 1:
+            weight = sort_cnt[0][1] + sort_cnt[1][1]
+            union = ({0: sort_cnt.popleft()[0], 1: sort_cnt.popleft()[0]}, weight)
+            for i, elem in enumerate(sort_cnt):
+                if elem[1] < weight:
+                    continue
+                sort_cnt.insert(i, union)
+                break
+            else:
+                sort_cnt.append(union)
+    else:
+        # Тут можно немного упростить
+        return {0: None, 1: sort_cnt[0][0]}
+    return sort_cnt[0][0]
+
+
+code_list = {}
+
+
+def crawl_tree(sort_cnt, path=''):
+    if isinstance(sort_cnt, dict):
+        crawl_tree(sort_cnt[0], path=f'{"0"}{path}')
+        crawl_tree(sort_cnt[1], path=f'{"1"}{path}')
+    else:
+        code_list[sort_cnt] = path
+
+
+def coding(string, res=''):
+    crawl_tree(haffman_tree(string))
+    for sym in string:
+        res = f'{res} {code_list[sym]}'
+    return res
+
+
+print('Результат:', coding(S))