Merge pull request fnplus#283 from SubCoder1/master

Added python implementation of doubly & circular linked list

Data Structures/Circular Linked List/Python/circular_linked_list.py

@@ -0,0 +1,82 @@
+class Node:
+    def __init__(self, value=None, nextNode=None, prevNode=None):
+        self.value = value
+        self.nextNode = nextNode
+        self.prevNode = prevNode
+
+    def get_next_node(self):
+        return self.nextNode
+
+    def get_prev_node(self):
+        return self.prevNode
+
+    def get_node_val(self):
+        return self.value
+
+class CircularLinkedList:
+    def __init__(self):
+        self.head = None
+        self.tail = None
+        self.chain_len = 0
+
+    def add_node_to_chain(self, value=None, Front=False):
+        new_node = Node(value=value)
+        if Front:
+            self.head.prevNode = new_node
+            new_node.nextNode = self.head
+            self.head = new_node
+            # To make the linked_list circular, chain's head & tail should be connected
+            self.head.prevNode = self.tail
+            self.tail.nextNode = self.head
+        else:
+            if self.head is None:
+                self.head = new_node
+                self.tail = self.head
+            else:
+                self.tail.nextNode = new_node
+                new_node.prevNode = self.tail
+                self.tail = new_node
+                self.tail.nextNode = self.head
+        self.chain_len += 1
+
+    def get_head_node(self):
+        return self.head
+
+    def get_tail_node(self):
+        return self.tail
+
+    def get_chain_length(self):
+        return self.chain_len
+
+    def print_chain(self, circular=False):
+        head = self.head
+        repeat = 0
+        while head:
+            print(' ',head.get_node_val(), "->", end='')
+            if head is self.get_tail_node():
+                if not repeat:
+                    repeat += 1
+                else:
+                    print("end_of_repetition")
+                    break
+            head = head.get_next_node()
+        else:
+            print(' chain_end')
+
+if __name__ == '__main__':
+    my_dl_list = CircularLinkedList()
+
+    my_dl_list.add_node_to_chain(1)
+    my_dl_list.add_node_to_chain(2)
+    my_dl_list.add_node_to_chain(3)
+    my_dl_list.add_node_to_chain(4)
+
+    print(f"Length of chain -> {my_dl_list.get_chain_length()}")
+
+    my_dl_list.print_chain()
+
+    print('-- Now adding a node to the front of the chain --')
+
+    my_dl_list.add_node_to_chain(5, Front=True)
+
+    my_dl_list.print_chain()

Data Structures/Doubly Linked List/Python/doubly_linked_list.py

@@ -0,0 +1,71 @@
+class Node:
+    def __init__(self, value=None, nextNode=None, prevNode=None):
+        self.value = value
+        self.nextNode = nextNode
+        self.prevNode = prevNode
+
+    def get_next_node(self):
+        return self.nextNode
+
+    def get_prev_node(self):
+        return self.prevNode
+
+    def get_node_val(self):
+        return self.value
+
+class DoublyLinkedList:
+    def __init__(self):
+        self.head = None
+        self.tail = None
+        self.chain_len = 0
+
+    def add_node_to_chain(self, value=None, Front=False):
+        new_node = Node(value=value)
+        if Front:
+            self.head.prevNode = new_node
+            new_node.nextNode = self.head
+            self.head = new_node
+        else:
+            if self.head is None:
+                self.head = new_node
+                self.tail = self.head
+            else:
+                self.tail.nextNode = new_node
+                new_node.prevNode = self.tail
+                self.tail = new_node
+        self.chain_len += 1
+
+    def get_head_node(self):
+        return self.head
+
+    def get_tail_node(self):
+        return self.tail
+
+    def get_chain_length(self):
+        return self.chain_len
+
+    def print_chain(self):
+        head = self.head
+        while head:
+            print(' ',head.value, "->", end='')
+            head = head.get_next_node()
+        else:
+            print(' chain_end')
+
+if __name__ == '__main__':
+    my_dl_list = DoublyLinkedList()
+
+    my_dl_list.add_node_to_chain(1)
+    my_dl_list.add_node_to_chain(2)
+    my_dl_list.add_node_to_chain(3)
+    my_dl_list.add_node_to_chain(4)
+
+    print(f"Length of chain -> {my_dl_list.get_chain_length()}")
+
+    my_dl_list.print_chain()
+
+    print('-- Now adding a node to the front of the chain --')
+
+    my_dl_list.add_node_to_chain(5, Front=True)
+
+    my_dl_list.print_chain()