Data-Strcture-Algorithm-using-Python

Topics:

• Queues
• Stacks
• Doubly Linked Lists
• Singly Linked Lists
• Binary Search Trees
• Tree Traversal
• Sortings
• Searchings
• Dynamic Programming
• Heap
• Graph

Queues

• Should have the methods: enqueue, dequeue, and len.
  • enqueue should add an item to the back of the queue.
  • dequeue should remove and return an item from the front of the queue.
  • len returns the number of items in the queue.

Doubly Linked Lists

• The ListNode class, which represents a single node in the doubly-linked list, has already been implemented for you. Inspect this code and try to understand what it is doing to the best of your ability.
• The DoublyLinkedList class itself should have the methods: add_to_head, add_to_tail, remove_from_head, remove_from_tail, move_to_front, move_to_end, delete, and get_max.
  • add_to_head replaces the head of the list with a new value that is passed in.
  • add_to_tail replaces the tail of the list with a new value that is passed in.
  • remove_from_head removes the head node and returns the value stored in it.
  • remove_from_tail removes the tail node and returns the value stored in it.
  • move_to_front takes a reference to a node in the list and moves it to the front of the list, shifting all other list nodes down.
  • move_to_end takes a reference to a node in the list and moves it to the end of the list, shifting all other list nodes up.
  • delete takes a reference to a node in the list and removes it from the list. The deleted node's previous and next pointers should point to each afterwards.
  • get_max returns the maximum value in the list.
• The head property is a reference to the first node and the tail property is a reference to the last node.

Binary Search Trees

• Should have the methods insert, contains, get_max.
  • insert adds the input value to the binary search tree, adhering to the rules of the ordering of elements in a binary search tree.
  • contains searches the binary search tree for the input value, returning a boolean indicating whether the value exists in the tree or not.
  • get_max returns the maximum value in the binary search tree.
  • for_each performs a traversal of every node in the tree, executing the passed-in callback function on each tree node value. There is a myriad of ways to perform tree traversal; in this case any of them should work.

Heaps

• Should have the methods insert, delete, get_max, _bubble_up, and _sift_down.
  • insert adds the input value into the heap; this method should ensure that the inserted value is in the correct spot in the heap
  • delete removes and returns the 'topmost' value from the heap; this method needs to ensure that the heap property is maintained after the topmost element has been removed.
  • get_max returns the maximum value in the heap in constant time.
  • get_size returns the number of elements stored in the heap.
  • _bubble_up moves the element at the specified index "up" the heap by swapping it with its parent if the parent's value is less than the value at the specified index.
  • _sift_down grabs the indices of this element's children and determines which child has a larger value. If the larger child's value is larger than the parent's value, the child element is swapped with the parent.

Sorting