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Ref: Carrano ch.21-24 and App.C
Specializations Of Lists
stacks: LIFO (last in, first out)
queues: FIFO (first in, first out)
priority queues
deques (double-ended)
Stacks
"remove" gets most recently-added
applications:
RPN solver
parentheses balance
Stack Operations
push: add a value
peek: "view" most recently added value
pop: remove most recently added value
java.util.Stack class
empty, Iterable
Stack Applications
parentheses balance checking
parse chars
push open parens
compare close parens to peek
pop if match found
else fail
reverse Polish notation (RPN) processing
push values onto stack
pop value(s) for unary or binary ops
Queues
"remove" gets least recently-added
applications:
service line
expression eval
Queue Operations
add: add a value
peek: "view" least recently added value
poll: remove least recently added value
java.util.Queue interface
java.util.LinkedList class
isEmpty, Iterable
Queue Applications
service line simulation
arrival rates
Poisson process
server model
serve front and remove, or...
...remove and serve front
statistics accumulation
expression conversion
Dijkstra algorithm
"infix" to RPN
build queue of RPN ops
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Priority Queues
"remove" gets highest value
application:
event queue
Priority Queue Operations
add: add a value
peek: "view" highest value
poll: remove highest value
java.util.Queue interface
java.util.PriorityQueue class
isEmpty, Iterable
Priority Queue Application
service line simulation: events
end-of-service events
schedule next event instead of...
...polling each queue
private static class eEvent implements Comparable<Event>
{
...
private int time;
...
public int compareTo(Event e)
{
return (time - e.time);
}
...
}
Arrays Of Lists
Queue<String>[] a = new Queue[10];
for (int i = 0; i < a.length; i++)
a[i] = new LinkedList<String>();
Stack<String>[] b = new Stack[10];
for (int i = 0; i < b.length; i++)
b[i] = new Stack<String>();
Queue<String>[] c = new Queue[10];
for (int i = 0; i < c.length; i++)
c[i] = new PriorityQueue<String>();
Cloning A List
for lists "a", this does not make a copy:
b = a; // 2 references to same list
but this does (e.g., for Stacks):
b = (Stack)a.clone();
Hash Maps
Java's hash tables
java.util.Map interface
java.util.HashMap class
application:
adding variables to expression evaluator
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