Stack

About Stack

What is a Stack ?

• stack is one-ended linear data structure which models a real world stack by having two primary operations, namely Push and Pop . and named Last In First Out

Instructions

• Explanation in an hour : ( 1:00:27 ) .

pop( ); // remove the first element in the data

push( “Onion” ); // add in the first element in the data

push( “Celery” )

push( “Watermelon”)

pop( )

pop( )

push( “Lettuce” )

When and Where is a Stack used ?

• Used by undo mechanisms in text editors.
• Used in compiler syntax checking for matching brackets and braces.
• Can be used to model a pile of books or plates.
• Used behind the scenes to support recursion by keeping track of previous functions calls.
• Can be used to do a Depth First Search ( DFS ) on a graph.

Complexity Analyses

Pushing	O( 1 )
Popping	O( 1 )
Peeking	O( 1 )
Searching	O( n )
Size	O( 1 )

Tower Of Hanoi

Explanation in a hour : ( 1:08:04 )