Stacks Stacks are incredibly useful data structures. An equivalent in real life.
Plates are added to the top of the stack and removed from the top—exactly like a stack in data structures.
Main functions:
top - View the top element
pop - Remove the top element
insert - Insert an element
Queues Queue is a very useful data structure.
When can imagine an example in life as we can see in airport security check or boarding where in the passengers are usually processed in the order they arrive or check in.
Main functions:
append - Add elements to the Right
pop - Remove the element from the right - Could be used for LIFO Operation
popleft - Remove first element from left - Used for normal FIFO Operation
Common import process for both stack and queues are using deque object from collections in python
We can utilize the queue as a stack, by setting up particular queue functions which can be direct used to perform the stack actions (LIFO). They are:
append - Adding elements in the right
pop - Remove the element from the right
Heaps Heaps are an awesome data structure. A heap data structure, especially a priority queue implemented as a heap, has real-life equivalents where elements are served based on priority, not arrival time.
Important use cases:
Emergency Room Triage Patients are treated based on the severity of their condition (priority), not by the order they arrived.
Task Scheduling in Operating Systems Tasks with higher priority (e.g., real-time processes) are scheduled before lower-priority ones.
Main functions to be used
heapq.heapify(input_list) : Pass the list that needs to heaped. Heapify will be default only do the min heap. So if we want to do a max heap, reverse the list, before passing to tbe heapified.
heapq.heappush(input_list, value) : Useful to push a new element. For min heap, pass the same value. For max heap, negate and pass in.
heapq.heappop(input_list) : Remove the lowest / max element from the heap. For lowest element, nothing additional to be done. For the max_element, after the top is removed, negate it to get the actual value
