Question

Returns all values in this entry tree together with their keys. * The order of outputs would be similar to level order traversal, * i.e., first you would get all values together with their keys in * first level from left to right, then second level, and so on. * If tree has no values then it would return {@code null}. * For the example image given in description, the * returned String[][] would look as follows: * * {{"IA","Grow"}, {"ISU","CS228"}} * * NOTE: In this method you are allowed to use * {@link java.util.LinkedList}. * * */

public String[][] getAll() {

// TODO

return null;

}

Answer 1

package edu.iastate.cs228.proj4;

/**

*

* @author

*

*

* An entry tree class.

*

*

*/

public class EntryTree

{

// Dummy root node.

// Made public for grading.

public Node root;

/**

*

* You are allowed to add at most TWO more data fields to

* EntryTree class of int type ONLY if you need to.

*

*/

// All made public for grading.

public class Node implements EntryNode

{

public Node child; // reference to the first child node

public Node parent; // reference to the parent node

public Node prev; // reference to the previous sibling

public Node next; // reference to the next sibling

public K key; // the key for this node

public V value; // the value at this node

public Node(K aKey, V aValue)

{

key = aKey;

value = aValue;

child = null;

parent = null;

prev = null;

next = null;

}

@Override

public EntryNode parent()

{

// TODO

return null;

}

@Override

public EntryNode child()

package edu.iastate.cs228.proj4;

/**

*

* @author

*

*

* An entry tree class.

*

*

*/

public class EntryTree

{

// Dummy root node.

// Made public for grading.

public Node root;

/**

*

* You are allowed to add at most TWO more data fields to

* EntryTree class of int type ONLY if you need to.

*

*/

// All made public for grading.

public class Node implements EntryNode

{

public Node child; // reference to the first child node

public Node parent; // reference to the parent node

public Node prev; // reference to the previous sibling

public Node next; // reference to the next sibling

public K key; // the key for this node

public V value; // the value at this node

public Node(K aKey, V aValue)

{

key = aKey;

value = aValue;

child = null;

parent = null;

prev = null;

next = null;

}

@Override

public EntryNode parent()

{

// TODO

return null;

}

@Override

public EntryNode child()

{

// TODO

return null;

}

@Override

public EntryNode next()

{

// TODO

return null;

}

@Override

public EntryNode prev()

{

// TODO

return null;

}

@Override

public K key()

{

// TODO

return null;

}

@Override

public V value()

{

// TODO

return null;

}

}

public EntryTree()

{

root = new Node(null, null);

}

/**

* Returns the value of the entry with a specified key sequence,

* or {@code null} if this tree contains no entry with this key

* sequence.

*

* This method returns {@code null} if {@code keyarr} is null or

* if its length is {@code 0}. If any element of {@code keyarr}

* is {@code null}, then the method throws a

* {@code NullPointerException}. The method returns the value of

* the entry with the key sequence in {@code keyarr} or {@code null}

* if this tree contains no entry with this key sequence. An example

* is given in provided sample input and output files to illustrate

* this method.

*

* @param keyarr Read description.

* @return Read description.

* @throws NullPointerException Read description.

*/

public V search(K[] keyarr)

{

// TODO

return null;

}

/**

*

* This method returns an array of type {@code K[]} with the longest

* prefix of the key sequence specified in {@code keyarr} such that

* the keys in the prefix label the nodes on the path from the root

* to a node. The length of the returned array is the length of the

* longest prefix.

*

* This method returns {@code null} if {@code keyarr} is {@code null},

* or if its length is {@code 0}. If any element of {@code keyarr} is

* {@code null}, then the method throws a {@code NullPointerException}.

* A prefix of the array {@code keyarr} is a key sequence in the

subarray

* of {@code keyarr} from index {@code 0} to any index {@code m>=0},

* i.e., greater than or equal to; the corresponding suffix is a key

* sequence in the subarray of {@code keyarr} from index {@code m+1} to

* index {@code keyarr.length-1}. The method returns an array of type

* {@code K[]} with the longest prefix of the key sequence specified in

* {@code keyarr} such that the keys in the prefix are, respectively,

* with the nodes on the path from the root to a node. The lngth of the

* returned array is the length of the longest prefix. Note that if the

* length of the longest prefix is {@code 0}, then the method returns

* {@code null}. This method can be used to select a shorted key

sequence

* for an {@code add} command to create a shorter path of nodes in the

* tree. An example is given in the attachment to illustrate how this

* method is used with the {@code #add(K[] keyarr, V aValue)} method.

*

* NOTE: In this method you are allowed to use

* {@link java.util.Arrays}'s {@code copyOf} method only.

*

* @param keyarr Read description.

* @return Read description.

* @throws NullPointerException Read description.

*/

public K[] prefix(K[] keyarr)

{

// TODO

return null;

}

/**

*

* This method returns {@code false} if {@code keyarr} is {@code null},

* its length is {@code 0}, or {@code aValue} is {@code null}. If any

* element of {@code keyarr} is {@code null}, then the method throws a

* {@code NullPointerException}.

*

* This method locates the node {@code P} corresponding to the longest

* prefix of the key sequence specified in {@code keyarr} such that the

* keys in the prefix label the nodes on the path from the root to the

node.

* If the length of the prefix is equal to the length of {@code keyarr},

* then the method places {@code aValue} at the node {@code P} (in place

of

* its old value) and returns {@code true}. Otherwise, the method

creates a

* new path of nodes (starting at a node {@code S}) labelled by the

* corresponding suffix for the prefix, connects the prefix path and

suffix

* path together by making the node {@code S} a child of the node {@code

P},

* and returns {@code true}. An example input and output files

illustrate

* this method's operation.

*

* NOTE: In this method you are allowed to use

* {@link java.util.Arrays}'s {@code copyOf} method only.

*

* @param keyarr Read description.

* @param Read description.

* @return Read description.

* @throws NullPointerException Read description.

*/

public boolean add(K[] keyarr, V aValue)

{

// TODO

return false;

}

/**

* Removes the entry for a key sequence from this tree and returns its

value

* if it is present. Otherwise, it makes no change to the tree and

returns

* {@code null}.

*

* This method returns {@code null} if {@code keyarr} is {@code null} or

its

* length is {@code 0}. If any element of {@code keyarr} is {@code

null}, then

* the method throws a {@code NullPointerException}. The method returns

* {@code null} if the tree contains no entry with the key sequence

specified

* in {@code keyarr}. Otherwise, the method finds the path with the key

sequence,

* saves the value field of the node at the end of the path, sets the

value field

* to {@code null}.

*

* The following rules are used to decide whether the current node and

higher

* nodes on the path need to be removed. The root cannot be removed. Any

node

* whose value is not {@code null} cannot be removed. Consider a non-

root node

* whose value is {@code null}. If the node is a leaf node (has no

children),

* then the node is removed. Otherwise, if the node is the parent of a

single

* child and the child node is removed, then the node is removed.

Finally, the

* method returns the saved old value.

*

*

* @param keyarr Read description.

* @return Read description.

* @throws NullPointerException Read description.

*

*/

public V remove(K[] keyarr)

{

// TODO

return null;

}

/**

*

* This method prints the tree on the console in the output format

* shown in provided sample output file. If the tree has no entry,

* then the method just prints out the line for the dummy root node.

*

*/

public void showTree()

{

// TODO

return;

}

/**

*

* Returns all values in this entry tree together with their keys.

* The order of outputs would be similar to level order traversal,

* i.e., first you would get all values together with their keys in

* first level from left to right, then second level, and so on.

* If tree has no values then it would return {@code null}.

*

* For the example image given in description, the

* returned String[][] would look as follows:

*

* {{"IA","Grow"}, {"ISU","CS228"}}

*

* NOTE: In this method you are allowed to use

* {@link java.util.LinkedList}.

*

*

*/

public String[][] getAll()

{

// TODO

return null;

}

}