create remove_duplicates.py

data_structures/linked_list/remove_duplicates.py

@@ -0,0 +1,159 @@
+class Node:
+    def __init__(self, data: int = None):
+        self.data = data
+        self.next = None
+
+    def __repr__(self):
+        """Returns a visual representation of the node and all its following nodes."""
+        string_rep = ""
+        temp = self
+        while temp:
+            string_rep += f"<{temp.data}> ---> "
+            temp = temp.next
+        string_rep += "<END>"
+        return string_rep
+
+
+def create(arr: list[int]) -> Node:
+    """
+    Creates a linked list from an array and returns the head of the linked list.
+
+    Args:
+        arr (list[int]): The array of integers.
+
+    Returns:
+        Node: The head of the linked list.
+
+    Example:
+        >>> arr = [1, 3, 5, 7, 9, 11, 11, 15, 17, 19]
+        >>> head = create(arr)
+        >>> head.data
+        1
+        >>> head.next.data
+        3
+    """
+    if not arr:
+        raise ValueError("The array is empty")
+
+    head = Node(arr[0])
+    current = head
+
+    for data in arr[1:]:
+        current.next = Node(data)
+        current = current.next
+
+    return head
+
+
+def display(head: Node) -> str:
+    """
+    Display the elements of the linked list.
+
+    Args:
+        head (Node): The head of the linked list.
+
+    Returns:
+        str: A visual representation of the linked list.
+
+    Example:
+        >>> arr = [1, 3, 5, 7, 9]
+        >>> head = create(arr)
+        >>> display(head)
+        '<1> ---> <3> ---> <5> ---> <7> ---> <9> ---> <END>'
+    """
+    result = ""
+    current = head
+    while current:
+        result += f"<{current.data}> ---> "
+        current = current.next
+    result += "<END>"
+    return result
+
+
+def count(head: Node) -> int:
+    """
+    Count the number of nodes in the linked list.
+
+    Args:
+        head (Node): The head of the linked list.
+
+    Returns:
+        int: The count of nodes in the linked list.
+
+    Example:
+        >>> arr = [1, 3, 5, 7, 9]
+        >>> head = create(arr)
+        >>> count(head)
+        5
+    """
+    count = 0
+    current = head
+    while current:
+        count += 1
+        current = current.next
+    return count
+
+
+def delete(head: Node, index: int) -> int:
+    """
+    Delete a node at a given index from the linked list and return its value.
+
+    Args:
+        head (Node): The head of the linked list.
+        index (int): The index at which the node should be deleted (1-based index).
+
+    Returns:
+        int: The value of the deleted node.
+
+    Example:
+        >>> arr = [1, 3, 5, 7, 9]
+        >>> head = create(arr)
+        >>> delete(head, 3)
+        5
+        >>> display(head)
+        '<1> ---> <3> ---> <7> ---> <9> ---> <END>'
+    """
+    if index < 1 or index > count(head):
+        return -1
+
+    if index == 1:
+        value = head.data
+        head = head.next
+        return value
+    else:
+        current = head
+        for _ in range(index - 2):
+            current = current.next
+        value = current.next.data
+        current.next = current.next.next
+        return value
+
+
+def remove_duplicates(head: Node):
+    """
+    Remove duplicates from a sorted linked list.
+
+    Args:
+        head (Node): The head of the sorted linked list.
+
+    Example:
+        >>> arr = [1, 3, 3, 5, 5, 7]
+        >>> head = create(arr)
+        >>> remove_duplicates(head)
+        >>> display(head)
+        '<1> ---> <3> ---> <5> ---> <7> ---> <END>'
+    """
+    current = head
+    while current and current.next:
+        if current.data == current.next.data:
+            current.next = current.next.next
+        else:
+            current = current.next
+
+
+if __name__ == "__main__":
+    arr = [1, 3, 5, 7, 9, 11, 11, 15, 17, 19]
+    head = create(arr)
+    remove_duplicates(head)
+    print("Linked List:")
+    print(display(head))