👉 In computer science, a "pushdown" or "pushdown stack" is an implementation of a stack data structure that uses a buffer to hold elements rather than pushing them onto the end of the list. This allows for efficient operations like popping and inserting from the beginning of the stack without having to check if the stack is empty first. In other words, a pushdown stack maintains its top element in memory at all times while allowing for fast access to the rest of the elements by using a buffer
