Merge pull request TheAlgorithms#182 from tonydelanuez/patch-1

Adding reverse() to singly-linked list

Author: harshildarji

data_structures/LinkedList/singly_LinkedList.py

@@ -47,4 +47,20 @@ def delete_tail(Head):#delete from tail
         return Head
 
     def isEmpty(Head):
-        return Head is None #Return if Head is none
+        return Head is None #Return if Head is none
+    
+    def reverse(Head):
+        prev = None
+        current = Head
+        
+        while(current):
+            # Store the current node's next node. 
+            next_node = current.next
+            # Make the current node's next point backwards
+            current.next = prev
+            # Make the previous node be the current node
+            prev = current
+            # Make the current node the next node (to progress iteration)
+            current = next_node
+        # Return prev in order to put the head at the end 
+        Head = prev