y.util.pq
Interface NodePQ

All Known Implementing Classes:

BHeapNodePQ

public interface NodePQ

Defines an interface for specialized priority queues that contains nodes which are prioritized by a comparable values.

Method Summary

void	add(Node v, Object priority) Adds the given node with the given priority to the queue.
void	clear() Makes this queue the empty queue.
boolean	contains(Node v) Returns whether or not the given node is contained in this queue.
void	decreasePriority(Node v, Object priority) Decreased the priority value of the given node.
Node	getMin() Returns he node with smallest priority in this queue.
Object	getPriority(Node v) Returns the current priority of the given node.
boolean	isEmpty() Returns whether or not this queue is empty
Node	removeMin() Removes the node with smallest priority from this queue.
int	size() Returns the number of nodes currently in this queue

Method Detail

add

public void add(Node v,
                Object priority)

Adds the given node with the given priority to the queue.

Precondition:

!contains(v)

decreasePriority

public void decreasePriority(Node v,
                             Object priority)

Decreased the priority value of the given node.

Preconditions:

contains(v)

c.compare(p,getPriority(v)) < 0, where c is the corresponding comparator for the priorities in this queue.

removeMin

public Node removeMin()

Removes the node with smallest priority from this queue.

Precondition:

!isEmpty()

Returns:

the removed node with smallest priority

getMin

public Node getMin()

Returns he node with smallest priority in this queue.

Precondition:

!isEmpty()

clear

public void clear()

Makes this queue the empty queue. in this queue.

contains

public boolean contains(Node v)

Returns whether or not the given node is contained in this queue.

getPriority

public Object getPriority(Node v)

Returns the current priority of the given node.

isEmpty

public boolean isEmpty()

Returns whether or not this queue is empty

size

public int size()

Returns the number of nodes currently in this queue