Merge pull request theja-m#8 from vcccaat/master

fix tail pointer in linked list

Data Structures - Linked Lists/Linked List.py

@@ -53,19 +53,15 @@ def insert(self,index,data):
   def remove(self,index):
     temp = self.head
     i=0
-    if index>self.length:
+    if index>=self.length:
       print("Entered wrong index")
-
+
+    if index == 0:
+      self.head = self.head.next
+      self.length -= 1   
+      return       
+
     while i<self.length:
-      if index == 0:
-        self.head = temp.next
-        self.length -= 1   
-        break       
-      if i == self.length-1:
-        temp.next = None
-        self.tail = temp
-        self.length -= 1
-        break 
       if i == index-1:
         temp.next = temp.next.next
         self.length-=1
@@ -99,6 +95,7 @@ def reverse(self):
 l.prepend(1)
 l.insert(2,99)
 l.insert(34,23)
-#l.remove(4)
+l.remove(5)
 l.reverse()
 l.printl()
+print(l.head.data, l.tail.data)

Data Structures - Stacks and Queues/Stacks using Linked List.py

@@ -19,28 +19,28 @@ def push(self,data):
       self.top = self.bottom
       self.length = 1
     else:
-      self.top.next = new_node
-      self.top = self.top.next
+      new_node.next = self.top
+      self.top = new_node
       self.length += 1
+      # print("top:",self.top.data,"top next:",self.top.next.data)
 
   def pop(self):
-    i = 1
-    curr_node = self.bottom
-    while i != self.length-1:
-      curr_node = curr_node.next
-      i+=1
-    popped_value = curr_node.next
-    curr_node.next = None
-    self.top = curr_node
+    if not self.top:
+      return None
+    holderPointer = self.top
+    self.top = self.top.next
     self.length -= 1
-    return popped_value.data
+    if self.length==0:
+      self.bottom = None
+    return holderPointer.data
 
   def printt(self):
-    temp = self.bottom
+    temp = self.top
     while temp != None:
       print(temp.data , end = ' -> ')
       temp = temp.next
     print()
+
 mystack = Stack()
 mystack.push('google')
 mystack.push('microsoft')

Dynamic Programming/Memoization.py

@@ -21,6 +21,24 @@ def memoizedadd80(n):
 print(memoizedadd80(6))
 
 #Memoization 2
+def memoizedadd80():
+  cache = {}
+
+  def memoized(n):
+	  if n in cache:
+	    return n + 80
+	  else:
+	    print('Long time')
+	    cache[n] = n+80
+	    return cache[n]
+  return memoized
+
+memo = memoizedadd80()
+print(memo(7))
+print(memo(7))
+
+
+
 # https://docs.python.org/3.3/library/functools.html --> Doc for lru_cache
 
 from functools import lru_cache