stack

• last in, first out. LIFO
• Stack: Abstract data type with the following operations:
• Push\(Key\): adds key to collection
• Key Top(): returns most recently-added key
• Key Pop(): removes and returns most recently-added key
• Boolean Empty(): are there any elements?
• solves balanced brackets problem : check if every prace has its own closing prace .
• psuedo code for balanced brackets: https://i.imgur.com/xIucIM7.png
• Stacks can be implemented with either an array or a linked list.
• Each stack operation is O(1): Push, Pop, Top, Empty.
• Stacks are ocassionaly known as LIFO queues.
• in a Array stack:
• adding the new elemnt of the stack to the end of the array, remove the last e of the array.
• array is limmited to the number of elements initialized with \(in some languages\).
• add using pushBack
• remove with popBack
• in a linked list stack:
• adding the new element to the begining \(head\) of the linked list, remove the head.
• add with pushFront
• remove with popfront