Merge branch 'master' into yashu

abranhe · web-flow · commit 5e59c93364f2 · 2020-10-19T22:23:48.000-04:00
diff --git a/algorithms/sorting/cocktail_sort.py b/algorithms/sorting/cocktail_sort.py
@@ -0,0 +1,26 @@
+def cocktailSort(array) 
+    n = len(array) 
+    swap = 1 
+    begin = 0 
+    end = n-1 
+    #Sorting start 
+    while (swap == 1): 
+        swap = 0 
+        
+    #sorting from begin 
+        for i in range (begin, end): 
+            if (a[i] > a[i+1]) : 
+                a[i], a[i+1]= a[i+1], a[i] 
+                swap=1 
+                
+        if (swap==0): 
+            break swap = 0 
+            
+        end = end-1 
+        #sorting from end 
+        for i in range(end-1, begin-1,-1): 
+            if (a[i] > a[i+1]): 
+                a[i], a[i+1] = a[i+1], a[i] 
+                swap = 1 
+        
+        begin = begin+1
diff --git a/data-structures/InorderTreeTraversal.py b/data-structures/InorderTreeTraversal.py
@@ -0,0 +1,50 @@
+class Node: 
+    """A binary tree node"""
+    def __init__(self, data, left=None, right=None): 
+        self.data = data 
+        self.left = left 
+        self.right = right 
+  
+  
+def morris_traversal(root): 
+    """Generator function for iterative inorder tree traversal"""
+  
+    current = root 
+      
+    while current is not None: 
+          
+        if current.left is None: 
+            yield current.data 
+            current = current.right 
+        else: 
+  
+            # Find the inorder predecessor of current 
+            pre = current.left 
+            while pre.right is not None and pre.right is not current: 
+                pre = pre.right 
+  
+            if pre.right is None: 
+  
+                # Make current as right child of its inorder predecessor 
+                pre.right = current 
+                current = current.left         
+  
+            else: 
+                # Revert the changes made in the 'if' part to restore the  
+                # original tree. i.e., fix the right child of predecessor 
+                pre.right = None
+                yield current.data 
+                current = current.right 
+              
+# Driver program to test the above function 
+
+root = Node(1, 
+            right = Node(3), 
+            left = Node(2, 
+                      left = Node(4), 
+                      right = Node(5) 
+            ) 
+       ) 
+  
+for v in morris_traversal(root): 
+    print(v, end=' ') 
diff --git a/data-structures/linked-lists/circulardoublylinkedlist.py b/data-structures/linked-lists/circulardoublylinkedlist.py
@@ -0,0 +1,109 @@
+class Node:
+    def __init__(self, data):
+       self.data = data
+       self.next = None
+       self.prev = None
+ 
+ 
+class CircularDoublyLinkedList:
+    def __init__(self):
+        self.first = None
+ 
+    def get_node(self, index):
+        current = self.first
+        for i in range(index):
+            current = current.next
+            if current == self.first:
+                return None
+        return current
+ 
+    def insert_after(self, ref_node, new_node):
+        new_node.prev = ref_node
+        new_node.next = ref_node.next
+        new_node.next.prev = new_node
+        ref_node.next = new_node
+ 
+    def insert_before(self, ref_node, new_node):
+        self.insert_after(ref_node.prev, new_node)
+ 
+    def insert_at_end(self, new_node):
+        if self.first is None:
+            self.first = new_node
+            new_node.next = new_node
+            new_node.prev = new_node
+        else:
+            self.insert_after(self.first.prev, new_node)
+ 
+    def insert_at_beg(self, new_node):
+        self.insert_at_end(new_node)
+        self.first = new_node
+ 
+    def remove(self, node):
+        if self.first.next == self.first:
+            self.first = None
+        else:
+            node.prev.next = node.next
+            node.next.prev = node.prev
+            if self.first == node:
+                self.first = node.next
+ 
+    def display(self):
+        if self.first is None:
+            return
+        current = self.first
+        while True:
+            print(current.data, end = ' ')
+            current = current.next
+            if current == self.first:
+                break
+ 
+ 
+a_cdllist = CircularDoublyLinkedList()
+ 
+print('Menu')
+print('insert <data> after <index>')
+print('insert <data> before <index>')
+print('insert <data> at beg')
+print('insert <data> at end')
+print('remove <index>') 
+print('quit')
+ 
+while True:
+    print('The list: ', end = '')
+    a_cdllist.display()
+    print()
+    do = input('What would you like to do? ').split()
+ 
+    operation = do[0].strip().lower()
+ 
+    if operation == 'insert':
+        data = int(do[1])
+        position = do[3].strip().lower()
+        new_node = Node(data)
+        suboperation = do[2].strip().lower() 
+        if suboperation == 'at':
+            if position == 'beg':
+                a_cdllist.insert_at_beg(new_node)
+            elif position == 'end':
+                a_cdllist.insert_at_end(new_node)
+        else:
+            index = int(position)
+            ref_node = a_cdllist.get_node(index)
+            if ref_node is None:
+                print('No such index.')
+                continue
+            if suboperation == 'after':
+                a_cdllist.insert_after(ref_node, new_node)
+            elif suboperation == 'before':
+                a_cdllist.insert_before(ref_node, new_node)
+ 
+    elif operation == 'remove':
+        index = int(do[1])
+        node = a_cdllist.get_node(index)
+        if node is None:
+            print('No such index.')
+            continue
+        a_cdllist.remove(node)
+ 
+    elif operation == 'quit':
+        break
