Python implementation for recursively reversing a linkedlist

anish03 · abranhe · commit 0de78cb53e47 · 2020-10-03T02:07:22.000-04:00
diff --git a/linkedlist/reverse_linkedlist.py b/linkedlist/reverse_linkedlist.py
@@ -0,0 +1,64 @@
+# Recursively reverse a linked list
+
+class Node:
+    def __init__(self,data):
+        self.data = data
+        self.next = None
+
+class LinkedList:
+    def __init__(self):
+        self.head = None
+        self.tail = None
+        self.count = 0 
+
+    def isEmpty(self):
+        if self.count == 0:
+            return True
+        return False
+    
+    def addnode(self,data):
+        new = Node(data)
+        if self.isEmpty():
+            self.head = new
+            self.tail = new
+            self.count += 1
+        else:
+            new.next = self.head
+            self.head = new
+            self.count += 1
+
+    def show(self):
+        list = ''
+        ptr = self.head
+        while ptr:
+            list += str(ptr.data)
+            list += '->'
+            ptr = ptr.next
+        print list
+    
+    def reverse(self,cur):
+        cur = cur
+        n = cur.next
+
+        if n.next:
+            self.reverse(cur.next)
+            n.next = cur
+            cur.next = None
+        else:
+            n.next = cur
+            self.head = n
+
+def main():
+    L = LinkedList()
+    L.addnode(89)
+    L.addnode(67)
+    L.addnode(21)
+    L.addnode(32)
+    L.addnode(2)
+    L.show()
+    L.reverse(L.head)
+    L.show()
+
+
+if __name__ == '__main__':
+    main()
