KuznetsovYuM/docs/data/1-st-exercise/phonebook_structures.py

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+
+def linked_list_add(head, name, phone):
+    curr = head
+    while curr is not None:
+        if curr['name'] == name:
+            curr['phone'] = phone
+            return head
+        curr = curr['next']
+
+    new_node = {'name': name, 'phone': phone, 'next': None}
+    if head is None:
+        return new_node
+
+    curr = head
+    while curr['next'] is not None:
+        curr = curr['next']
+    curr['next'] = new_node
+    return head
+
+
+def linked_list_find(head, name):
+    curr = head
+    while curr is not None:
+        if curr['name'] == name:
+            return curr['phone']
+        curr = curr['next']
+    return None
+
+
+def linked_list_remove(head, name):
+    if head is None:
+        return None
+
+    if head['name'] == name:
+        return head['next']
+
+    prev = head
+    curr = head['next']
+    while curr is not None:
+        if curr['name'] == name:
+            prev['next'] = curr['next']
+            return head
+        prev = curr
+        curr = curr['next']
+    return head
+
+
+def linked_list_collect_all(head):
+    records = []
+    curr = head
+    while curr is not None:
+        records.append((curr['name'], curr['phone']))
+        curr = curr['next']
+    records.sort(key=lambda pair: pair[0])
+    return records
+
+
+# Quick test 
+if __name__ == '__main__':
+    lst = None
+    lst = linked_list_add(lst, 'Alice', '111-222')
+    lst = linked_list_add(lst, 'Bob', '333-444')
+    lst = linked_list_add(lst, 'Alice', '555-666')
+    print(linked_list_find(lst, 'Alice'))  # 555-666
+    print(linked_list_collect_all(lst))    # [('Alice','555-666'), ('Bob','333-444')]
+    lst = linked_list_remove(lst, 'Bob')
+    print(linked_list_collect_all(lst))    # [('Alice','555-666')]