[1] Implement hash table based on linked list buckets

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

@@ -1,4 +1,3 @@
-
 def linked_list_add(head, name, phone):
     curr = head
     while curr is not None:
@@ -30,10 +29,8 @@ def linked_list_find(head, name):
 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:
@@ -55,13 +52,49 @@ def linked_list_collect_all(head):
     return records
 
 
+def _hash_bucket_index(key, table_size):
+    return hash(key) % table_size
+
+
+def hash_table_create(bucket_count=10):
+    return [None] * bucket_count
+
+
+def hash_table_put(table, name, phone):
+    idx = _hash_bucket_index(name, len(table))
+    table[idx] = linked_list_add(table[idx], name, phone)
+    return table
+
+
+def hash_table_get(table, name):
+    idx = _hash_bucket_index(name, len(table))
+    return linked_list_find(table[idx], name)
+
+
+def hash_table_remove(table, name):
+    idx = _hash_bucket_index(name, len(table))
+    table[idx] = linked_list_remove(table[idx], name)
+    return table
+
+
+def hash_table_collect_all(table):
+    all_records = []
+    for head in table:
+        curr = head
+        while curr is not None:
+            all_records.append((curr['name'], curr['phone']))
+            curr = curr['next']
+    all_records.sort(key=lambda pair: pair[0])
+    return all_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')]
+    ht = hash_table_create(5)
+    ht = hash_table_put(ht, 'Alice', '111')
+    ht = hash_table_put(ht, 'Bob', '222')
+    ht = hash_table_put(ht, 'Alice', '333')
+    print(hash_table_get(ht, 'Alice'))   # 333
+    print(hash_table_get(ht, 'Charlie')) # None
+    ht = hash_table_remove(ht, 'Bob')
+    print(hash_table_collect_all(ht))    # [('Alice','333')]