Creativity section of Exercises

Author: MayankShah1

.idea/workspace.xml

@@ -0,0 +1,74 @@
+class Empty(Exception):
+    """Error attempting to access an element from an empty container"""
+    pass
+
+
+class LinkedStack:
+    """LIFO Stack implementation using a singly linked list for storage"""
+
+    # --------------- nested _Node class -----------------
+    class _Node:
+        """Lightweight, nonpublic class for storing a singly linked node."""
+        __slots__ = '_element', '_next'
+
+        def __init__(self, element, next):
+            self._element = element
+            self._next = next
+
+    # -------------------- stack methods ------------------
+
+    def __init__(self):
+        """Create an empty stack"""
+
+        self._header = self._Node(None,None)
+        self._size = 0
+
+    def __len__(self):
+        """Return the number of elements in stack"""
+        return self._size
+
+    def is_empty(self):
+        """Return True if stack is empty"""
+        return self._size == 0
+
+    def push(self, e):
+        """Add element to the top of stack"""
+        newest = self._Node(e, self._header._next)
+        self._header._next = newest
+        self._size += 1
+
+    def top(self):
+        """Return the element at the top of the stack.
+
+        Raise Empty exception if stack is empty.
+        """
+        if self.is_empty():
+            raise Empty('Stack is empty')
+        return self._header._next._element
+
+    def pop(self):
+        """ Return and remove the element at the top of the stack
+
+        Raise empty exception if stack is empty. 
+        """
+        if self.is_empty():
+            raise Empty('Stack is empty')
+        answer = self._header._next._element
+        self._header = self._header._next
+        self._size -= 1
+        return answer
+
+
+# Testing
+if __name__ == "__main__":
+    stack = LinkedStack()
+
+    stack.push(10)
+    stack.push(20)
+    stack.push(30)
+    print(stack.top())
+    stack.push(40)
+    print(stack.pop())
+    print(stack.top())
+    print(stack.pop())
+    print(stack.top())

07-Linked-Lists/Exercises/Creativity/C7-24.py

@@ -0,0 +1,104 @@
+class Empty(Exception):
+    """Error attempting to access an element from an empty container"""
+    pass
+
+class LinkedQueue:
+    """FIFO Queue implementation using a singly linked list for storage"""
+
+    # --------------- nested _Node class -----------------
+    class _Node:
+        """Lightweight, nonpublic class for storing a singly linked node."""
+        __slots__ = '_element', '_next'
+
+        def __init__(self, element, next):
+            self._element = element
+            self._next = next
+
+
+    # -------------------- queue methods ------------------
+
+    def __init__(self):
+        """Create an empty queue."""
+
+        self._head = None
+        self._tail = None
+        self._size = 0
+
+    def __len__(self):
+        """Return the size of queue."""
+        return self._size
+
+    def is_empty(self):
+        """Return True if queue is empty."""
+        return self._size == 0
+
+    def first(self):
+        """Return the first element of the queue.
+
+        Raise Empty exception if stack is empty.
+        """
+        if self.is_empty():
+            raise Empty('Queue is empty')
+        return self._head._element
+
+    def enqueue(self,e):
+        """Add an element at the back of the queue"""
+        newest = self._Node(e, None)
+        if self.is_empty():
+            self._head = newest
+        else:
+            self._tail._next = newest
+        self._tail = newest
+        self._size += 1
+
+    def dequeue(self):
+        """ Return and remove the element at the front of the queue.
+
+        Raise empty exception if queue is empty. 
+        """
+        if self.is_empty():
+            raise Empty('Queue is empty.')
+        answer = self._head._element
+        self._head = self._head._next
+        if self.is_empty():
+            self._tail = None
+        return answer
+
+    def concatenate(self, other):
+        """Concatenates the other queue"""
+        self._tail._next = other._head
+        self._tail = other._tail
+        self._size += other._size
+        other._size = 0
+        other._head = None
+
+    def __str__(self):
+        elements = []
+        walk = self._head
+        while walk is not None:
+            elements.append(str(walk._element) + ' ')
+            walk = walk._next
+        return ''.join(elements)
+
+# Testing
+if __name__ == "__main__":
+    queue = LinkedQueue()
+
+    queue.enqueue(10)
+    queue.enqueue(20)
+    queue.enqueue(30)
+    print(queue)
+    queue.enqueue(40)
+    print(queue)
+    queue.dequeue()
+    print(queue)
+
+    queue_two = LinkedQueue()
+    queue_two.enqueue(50)
+    queue_two.enqueue(60)
+    print(queue_two)
+
+    queue.concatenate(queue_two)
+    print(queue)
+    print(queue_two)
+

07-Linked-Lists/Exercises/Creativity/C7-26.py

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+class Empty(Exception):
+    """Error attempting to access an element from an empty container"""
+    pass
+
+class LinkedQueue:
+    """FIFO Queue implementation using a singly linked list for storage"""
+
+    # --------------- nested _Node class -----------------
+    class _Node:
+        """Lightweight, nonpublic class for storing a singly linked node."""
+        __slots__ = '_element', '_next'
+
+        def __init__(self, element, next):
+            self._element = element
+            self._next = next
+
+
+    # -------------------- queue methods ------------------
+
+    def __init__(self):
+        """Create an empty queue."""
+
+        self._head = None
+        self._tail = None
+        self._size = 0
+
+    def __len__(self):
+        """Return the size of queue."""
+        return self._size
+
+    def is_empty(self):
+        """Return True if queue is empty."""
+        return self._size == 0
+
+    def first(self):
+        """Return the first element of the queue.
+
+        Raise Empty exception if stack is empty.
+        """
+        if self.is_empty():
+            raise Empty('Queue is empty')
+        return self._head._element
+
+    def enqueue(self,e):
+        """Add an element at the back of the queue"""
+        newest = self._Node(e, None)
+        if self.is_empty():
+            self._head = newest
+        else:
+            self._tail._next = newest
+        self._tail = newest
+        self._size += 1
+
+    def dequeue(self):
+        """ Return and remove the element at the front of the queue.
+
+        Raise empty exception if queue is empty. 
+        """
+        if self.is_empty():
+            raise Empty('Queue is empty.')
+        answer = self._head._element
+        self._head = self._head._next
+        if self.is_empty():
+            self._tail = None
+        return answer
+
+# Testing
+if __name__ == "__main__":
+    queue = LinkedQueue()
+
+    queue.enqueue(10)
+    queue.enqueue(20)
+    queue.enqueue(30)
+    print(queue.first())
+    queue.enqueue(40)
+    print(queue.dequeue())
+