Reimplemented the main logic using a tip by Gbowne

goulag_sort/goulagsort.py

@@ -1,119 +1,71 @@
-def send_to_goulag(input_list:list)-> list :
-    """Sorts a list of numbers using the unique "Goulag Sort" method.
+def send_to_goulag(main_list: list) -> list:
+    if not main_list:
+        return [] # Se a lista de entrada está vazia, retorna vazio
 
-    This algorithm processes a list of numbers through a distinctive iterative and
-    recursive procedure, inspired by the "Stalin Sort" concept. Here's how it operates:
+    # Se a lista tem 1 ou 0 elementos, ela já está ordenada
+    if len(main_list) <= 1:
+        return main_list
 
-    1.  **Iterative Filtering:** It iterates through the main list. If an element
-        is found to be greater than its subsequent element, the subsequent element
-        is moved to a temporary holding list (`temp`). The main list then continues
-        with the remaining elements.
+    filtered_list = []
+    gulag_list = []
 
-    2.  **Recursive Processing of Held Items:** If the `temp` list contains more than
-        one item, the `send_to_goulag` algorithm recursively processes `temp`. This
-        filtering and holding process continues until the sub-list contains a single
-        item or becomes empty.
+    # O primeiro elemento sempre vai para a filtered_list como ponto de partida
+    filtered_list.append(main_list[0])
 
-    3.  **Partial Re-insertion:** After the recursive calls (or if `temp` was empty/single-item),
-        the algorithm attempts to re-insert the elements from `temp` back into the main list.
-        This re-insertion is performed by finding a suitable position where the held item
-        is less than the current element in the main list, maintaining a partial order.
+    # Percorre o restante da lista original (a partir do segundo elemento)
+    # com um único ponteiro 'i'
+    for i in range(1, len(main_list)):
+        current_item = main_list[i]
+        last_in_filtered = filtered_list[-1] # Pega o último item já colocado na filtered_list
 
-    4.  **Final Appending:** Any remaining elements in `temp` that were not re-inserted
-        into the middle of the list are then appended to the end of the main list.
+        if current_item >= last_in_filtered:
+            # Se o item atual mantém a ordem com o que já foi filtrado, adicione-o
+            filtered_list.append(current_item)
+        else:
+            # Se o item atual quebra a ordem, ele é "rejeitado" para o gulag
+            gulag_list.append(current_item)
 
-    For a more detailed step-by-step explanation of the algorithm's flow, please refer to:
-    :ref:`goulag_sort_detailed_explanation`.
+    if len(gulag_list) > 1:
+        gulag_list = send_to_goulag(gulag_list)
+
+    filtered_list = merge_sorted_lists_efficient(filtered_list,gulag_list)
+
+    return filtered_list
+
+
+def merge_sorted_lists_efficient(list1: list, list2: list) -> list:
+    """
+    Mescla duas listas ordenadas de forma eficiente, criando uma nova lista resultado.
+    Evita as operações custosas de insert/pop no meio das listas.
 
     Args:
-        input_list (list): The list of numbers to be processed and sorted.
-                           This list will be modified **in-place**.
+        list1: A primeira lista ordenada.
+        list2: A segunda lista ordenada.
 
     Returns:
-        list: The list after being processed by the Goulag Sort algorithm. The result
-              is an ordered list.
-
-    Examples:
-        >>> from goulag_sort import send_to_goulag
-        >>> my_list = [5, 2, 8, 1, 9, 4]
-        >>> send_to_goulag(my_list)
-        [1, 2, 4, 5, 8, 9]
-
-        >>> empty_list = []
-        >>> send_to_goulag(empty_list)
-        []
+        Uma NOVA lista contendo todos os elementos de list1 e list2 mesclados e ordenados.
     """
+    merged_list = []
+    ptr1 = 0  # Ponteiro para list1
+    ptr2 = 0  # Ponteiro para list2
 
-
-    idx = 0
-    temp = []
-    is_sorted = True
-    while True:
-
-        if not input_list:
-            return []
-
-        if len(input_list)<=1:
-            return input_list
-
-
-
-        while idx < len(input_list) - 1:
-            if input_list[idx] > input_list[idx + 1]:
-                temp.append(input_list[idx + 1])
-                # pop(idx+1) é uma operação O(N) no pior caso
-                input_list.pop(idx + 1)
-            else:
-                idx += 1
-
-        # Chamada recursiva (pode adicionar complexidade se for muito frequente)
-        if len(temp) > 1:
-            temp = send_to_goulag(temp)
-
-        idx = 0
-        # Loop para reinserir elementos de 'temp' na lista principal
-        merge_two_sorted_lists_in_place(input_list,temp)
-
-        if temp:
-            input_list.extend(temp)  # extend é O(k) onde k é o tamanho de temp
-            temp.clear()
-
-        for i in range(len(input_list) - 1):
-            if input_list[i] > input_list[i + 1]:
-                is_sorted = False
-                break
-        if is_sorted:
-            return input_list
-
-def merge_two_sorted_lists_in_place(list1: list, list2: list) -> list:
-
-    if not list2:
-        return list1
-    if not list1:
-        list1.extend(list2)
-        list2.clear()
-        return list1
-
-
-    ptr1 = 0
-    ptr2 = 0
-
-
+    # Enquanto houver elementos em ambas as listas para comparar
     while ptr1 < len(list1) and ptr2 < len(list2):
-        if list1[ptr1] > list2[ptr2]:
-
-            list1.insert(ptr1, list2[ptr2])
-
+        if list1[ptr1] <= list2[ptr2]:  # Note o <= para estabilidade (mantém ordem de iguais)
+            merged_list.append(list1[ptr1])
             ptr1 += 1
-
-            list2.pop(ptr2)
         else:
+            merged_list.append(list2[ptr2])
+            ptr2 += 1
 
+    # Adicionar quaisquer elementos restantes de list1 (se houver)
+    while ptr1 < len(list1):
+        merged_list.append(list1[ptr1])
         ptr1 += 1
 
+    # Adicionar quaisquer elementos restantes de list2 (se houver)
+    while ptr2 < len(list2):
+        merged_list.append(list2[ptr2])
+        ptr2 += 1
 
-    if list2:
-        list1.extend(list2)
-        list2.clear() # Esvazia list2
-
-    return list1
+    return merged_list