Download Assignment 4 for Data Structures | CS 230 and more Assignments Data Structures and Algorithms in PDF only on Docsity!
CS230 Data Structures Handout # 27
Prof. Lyn Turbak March 29, 2007
Wellesley College Revised April 4, 2007
Problem Set 4 Due: 1:30pm Tuesday, April 10
This is the final version of PS4. Note that Problem 2 is now posted on the web at
http://cs.wellesley.edu/~cs230/ps4-color-game. The problem set is now due at 1:
on Tuesday, April 10.
Overview:
The purpose of this assignment is to give you practice with (1) using queues, tables, and sets in
a simple web-crawling scenario and (2) building a GUI from scratch. As usual, it is recommended
that you (1) start early and (2) work with a partner (a different one than you worked with on PS
Submission:
Each team should turn in a single hardcopy submission packet for all problems by slipping it
under Lyn’s office door by 6pm on the due date. The packet should include:
1. a team header sheet (see the end of this assignment for the header sheet) indicating the time
that you (and your partner, if you are working with one) spent on the parts of the assignment.
2. your final version of WebCrawler.java from Problem 1.
3. a transcript of your WebCrawler test cases for Problem 1.
4. your final version of GuessTheColor.java from Problem 2.
Each team should also submit a single softcopy (consisting of your entire final ps4 directory)
to the drop directory ~cs230/drop/ps4/username, where username is the username of one of the
team members (indicate which drop folder you used on your hardcopy header sheet). To do this,
execute the following Linux commands in the team member’s account where the code is stored:
cd /students/username/cs
cp -R ps4 ~cs230/drop/ps4/username/
Problem 1 [35]: A Web Crawler
Background
Modern web search engines like Google have sophisticated web page indexing mechanisms that
make it possible to quickly list web pages containing a given set of keywords. Conceptually, there
are two distinct phases to web page indexing:
1. An indexing phase in which a very large database (think table) is constructed by processing
all the words in each of the web pages that is indexed.
2. A query phase in which users submit keyword queries and some subset of the web pages
in the database matching these queries (hopefully the most relevant ones) are found and
displayed.
Since web pages are constantly changing and new web pages are being published all the time,
the indexing phase is an ongoing process that is interleaved with the query phase. The indexing
phase is largely carried out by automated agents variously known as web crawlers, web spiders,
and web robots. After indexing the contents of a page, these agents follow one or more links
mentioned on page and recursively index the pages that are the targets of these links.
In this problem, you will implement an extremely simple web crawler that indexes a subset of
the web pages that are reachable from the web pages in a given list. This web crawler is a modified
version of the file indexer that you studied in Lab 8. Like the file indexer, the web crawler uses a
table to map each word encountered in the indexing process to a set of all the web pages in which
it was found. Unlike the file indexer, the web crawler has to follow links from one web page to
another.
For example, consider Fig. 1, which shows the links between some sample web pages.^1 From
index.html, four pages can be reached by one link: decartes.txt, seuss.txt, popeye.html, and
dome.html. Some of these pages themselves have links that can also be followed.
The diagram in Fig. 1 is an example of a directed graph, a structure in which nodes are
connected by directed edges. In a directed graph, there may be more than one path from one node
to another. For example, in Fig. 1 it is also possible to get from index.html to descartes.txt
by following one link from index.html to popeye.html and then following another link from
popeye.html to descartes.txt. A directed graph may also contain cycles — nonempty paths
that go from a node back to itself. For example, the path from index.html to gdome.html and
back to index.html is a cycle.
Assume that our web crawler is always visiting a particular page. The basic strategy of the
crawler is to index all the words at that page and to add the targets of the links that originate at
that page to a queue of pages to visit. When the crawler is done indexing a page, it dequeues
the next page from the queue and begins to process it similarly.
In order to avoid duplicating work or getting stuck in an infinite loop, we want our web crawler
to avoid visiting any page more than once. For this purpose, the crawler will maintain a set of
already-seen pages. Whenever it encounters a link to another page, the crawler will first check
if that page is in the set. If so, it will not add the page to its queue. If not, it will add the page to
its queue, and will also add it to the already-seen set.
Because the graph of web pages is so vast, we cannot reasonably expect that our simple crawler
will be able to visit all reachable pages. So we will limit it to visit only those pages that are
reachable by following no more than some given number of links (called the maximum distance)
from a starting page. For example, if the crawler starts at the page named index.html in Fig. 1,
then here are the pages it will visit for some values of the maximum distance:
Maximum Pages Visited
Distance
0 index.html
1 index.html, descartes.txt, seuss.txt, popeye.html, gdome.html
2 index.html, descartes.txt, seuss.txt, popeye.html, gdome.html, ~gdome
3 index.html, descartes.txt, seuss.txt, popeye.html, gdome.html, ~gdome,
cs.wellesley.edu, list.html, table.html, cookies.html
Finding Links in a Page
Within an HTML page, links have the form link-text , where link-
text is the highlighted text that appears in the browser, and link-url is the URL (Uniform Resource
Locator, i.e., the address) of the web page that is the target of the link. The URL may either be
absolute, in which case it specifies the entire address of the page or relative, in which case it
specifieds an address of the page relative to the address of the current page. For example, the
URL http://cs.wellesley.edu/~gdome in dome.html is absolute, while the URL dome.html in
index.html and ./ in dome.html are relative URLs. A relative URL can be transformed to an
absolute URL by merging its information with the absolute URL of the page in which it occurs.
For example, suppose the absolute URL of index.html is
(^1) The page named index.html resides at http://cs.wellesley.edu/~cs230/amness/index.html, and all the other
pages are reachable from it.
Figs. 3 and 3 show two examples of using URLWordsAndLinks to process files. The file index.html
is found to have four links, while the file dome.html is found to have two links.
For more details on the URLWordsAndLinks class, see Appendix A.
[fturbak@puma web-crawler] java URLWordsAndLinks http://cs.wellesley.edu/~cs230/amness/index.html 0:HTML 1:TITLE 2:Amness 3:Quotes 4:/TITLE 5:BODY 6:H 7:Famous 8:I 9:Am 10:Quotes 11:/H 12:UL 13:LI 14:A 15:HREF 16:descartes.txt 17:link=http://cs.wellesley.edu/~cs230/amness/descartes.txt 18:Descartes 19:/A 20:LI 21:A 22:HREF 23:seuss.txt 24:link=http://cs.wellesley.edu/~cs230/amness/seuss.txt 25:Seuss 26:/A 27:LI 28:A 29:HREF 30:popeye.html 31:link=http://cs.wellesley.edu/~cs230/amness/popeye.html 32:Popeye 33:/A 34:LI 35:A 36:HREF 37:dome.html 38:link=http://cs.wellesley.edu/~cs230/amness/dome.html 39:Dome 40:/A 41:/UL 42:/BODY 43:/HTML [fturbak@puma web-crawler]
Figure 2: Using URLWordsAndLinks to enumerate the words and links of index.html.
The Web Crawler in Action
The web crawler for this assignment is implemented in an application named WebCrawler.
Invoking this application on a non-negative number n and a URL indexes all web pages that are
at most n links away from the page at the URL. During the indexing phase, messages are printed
whenever a web page is enqueued on the queue of pages to visit and whenever a web page is actually
indexed. The indexer indexes lower-case versions of all the words in each page, associating every
[fturbak@puma web-crawler] java URLWordsAndLinks http://cs.wellesley.edu/~cs230/amness/dome.html 0:P 1:I 2:think 3:therefore 4:iambic 5:pentameter 6:A 7:HREF 8:http://cs.wellesley.edu/~gdome 9:link=http://cs.wellesley.edu/~gdome 10:Georgia 11:Dome 12:/A 13:P 14:A 15:HREF 16:./ 17:link=http://cs.wellesley.edu/~cs230/amness/ 18:Back 19:/A 20:to 21:index [fturbak@puma web-crawler]
Figure 3: Using URLWordsAndLinks to enumerate the words and links of dome.html.
word with a set of all the web pages in which it was found.
After the indexing phase, a read/query/print loop is launched in which the user can type a
sequence of words. The program responds with a list of all pages in the index in which all the
words were found. The special query #contents will display the entire contents of the index.
Examples of the WebCrawler application are shown in Appendix B. An executable version of
this program can be found in ~cs230/ps4/web-crawler/test. You are encouraged to experiment
with this program before continuing with this problem.
Your Task
A skeleton of a program implementing the simple web crawler described above is presented
in Figs. 4–5. The skeleton contains a complete implementation of the main method and the
read/query/print loop, as well as a fleshed-out WebCrawler constructor method.
Your task is to complete the skeleton by implementing the code that indexes all web pages within
maxDistance of the starting page. You should do this by fleshing out the indexPagesStartingAt()
method. In order to make your code more readable, you are encouraged to write helper methods
as well. Your methods may use the four instance variables of the WebCrawler class:
- maxDistance: the maximum number of links from the starting page for a web page to be
indexed.
- indexTable: a table that associates each word (i.e., lower-case string) encountered in the
indexing phase with a set of the URLs of all the web pages in which it was found.
- urlsSeen: a set of all the URLs seen already (i.e., the URLs of those pages that have been
indexed or are on the queue to be indexed).
- queue: a queue of all the URLs to be indexed. The elements of this queue are instances of
the Edge class (Fig. 6), which pairs a URL (i.e., a string) for a web page with an integer
indicating the distance of that page from the starting page.
// Display the names of web pages in indexTable containing all the words. public void processQuery (String [] words) { if (words.length >= 1) { // Find set of files s containing first keyword. Must copy this set to avoid mutating set // in table with subsequent intersections. If the mutations were performed on the original // rather than the copy, the set value associated with the first keyword in the table // would be mutated -- a very undesirable behavior! Set files = lookup(words[0].toLowerCase()).copy(); // Iteratively intersect s with sets for remaining keywords for (int i = 1; i < words.length; i++) { files.intersection(lookup(words[i].toLowerCase())); } // Now s contains the set of all files with all keywords. Display them: Iterator iter = files.iterator(); while (iter.hasNext()) { System.out.println(iter.next()); } // Note: could replace the above by IterableOps.display(files); } }
// Helper method that acts like get() but returns an empty set // for any word that is not in indexTable private Set lookup (String x) { Set result = indexTable.get(x); if (result == null) { return new SetVectorSorted(); } else { return result; } }
// Display a usage message for this application public static void usage() { System.out.println("usage: java WebCrawler "); }
// Entry point for the WebCrawler application public static void main (String [] args) { if (args.length >= 2) { try { int maxDist = Integer.parseInt(args[0]); if (maxDist >= 0) { WebCrawler crawler = new WebCrawler(maxDist); crawler.indexPagesStartingAt(args[1]); crawler.queryLoop(); } else { System.out.println("maxDistance must be nonnegative:" + maxDist); usage(); } } catch (NumberFormatException ex) { System.out.println("maxDistance must be a number!" + args[0]); usage(); } } else { usage(); } }
}
Figure 5: Skeleton for the WebCrawler class, part 2
/** An instance of the Edge class represents a link to a URL that is a specified distance away from another web page. */
class Edge {
public String url; public int distance;
public Edge (String url, int distance) { this.url = url; this.distance = distance; }
public String toString () { return "Edge[url=" + url + "; distance=" + distance + "]"; }
}
Figure 6: Implementation of the Edge class.
Notes
1. All the code for this problem can be found in the directory ~/cs230/ps4/web-crawler. As
usual, you will need to execute cvs update -d to grab this directory.
2. As mentioned earlier, the subdirectory ~/cs230/ps4/web-crawler/test contains an exe-
cutable version of the program you can use for testing purposes.
3. The isLink() and linkURL() class methods from URLWordsAndLinks (see Appendix A) are
handy for manipulating the links produced by a URLWordsAndLinks iterator.
4. When you compile WebCrawler, you may get the following warning, which is safe to ignore:
Note: Some input files use unchecked or unsafe operations.
Note: Recompile with -Xlint:unchecked for details.
5. If you try java WebCrawler 5 http://cs.wellesley.edu/~cs230/amness/, the crawler
will encounter many links that do not exist or cannot be read. Your web crawler should
display a reasonable message for non-existent links and continue indexing.
6. This implementation of WebCrawler uses the SetVectorSorted implementation of sets and
the TableVectorSorted implementation of tables. These work fine for a moderate number
of elements (on the order of 10^5 ), but begin to noticeably slow down at around 10^6 elements.
For larger number of elements, more efficient versions of these data structures should be use.
However, you will not encounter such large number of elements on this problem if you keep
maxDistance small.
7. Your should submit a testing transcript for this problem. Your transcript should contain at
least the test cases in Appendix B, but may contain additional test cases as well.
Problem 2 [65]: The Color Guessing Game
The description for this problem can be found on the web at http://cs.wellesley.edu/
~cs230/ps4-color-game. For this problem, you should implement the GuessTheColor.java game
described there in the directory ~cs230/ps4/color-game.
li: SetVectorSorted[http://cs.wellesley.edu/~cs230/amness/] popeye: SetVectorSorted[http://cs.wellesley.edu/~cs230/amness/] popeye.html: SetVectorSorted[http://cs.wellesley.edu/~cs230/amness/] quotes: SetVectorSorted[http://cs.wellesley.edu/~cs230/amness/] seuss: SetVectorSorted[http://cs.wellesley.edu/~cs230/amness/] seuss.txt: SetVectorSorted[http://cs.wellesley.edu/~cs230/amness/] title: SetVectorSorted[http://cs.wellesley.edu/~cs230/amness/] ul: SetVectorSorted[http://cs.wellesley.edu/~cs230/amness/]
query> Thank you for using the indexing query system!
[fturbak@puma web-crawler] java WebCrawler 1 http://cs.wellesley.edu/~cs230/amness/ Indexing Edge[url=http://cs.wellesley.edu/~cs230/amness/; distance=0] Enqueueing Edge[url=http://cs.wellesley.edu/~cs230/amness/descartes.txt; distance=1] Enqueueing Edge[url=http://cs.wellesley.edu/~cs230/amness/seuss.txt; distance=1] Enqueueing Edge[url=http://cs.wellesley.edu/~cs230/amness/popeye.html; distance=1] Enqueueing Edge[url=http://cs.wellesley.edu/~cs230/amness/dome.html; distance=1] Indexing Edge[url=http://cs.wellesley.edu/~cs230/amness/descartes.txt; distance=1] Indexing Edge[url=http://cs.wellesley.edu/~cs230/amness/seuss.txt; distance=1] Indexing Edge[url=http://cs.wellesley.edu/~cs230/amness/popeye.html; distance=1] Indexing Edge[url=http://cs.wellesley.edu/~cs230/amness/dome.html; distance=1]
query> am http://cs.wellesley.edu/~cs230/amness/ http://cs.wellesley.edu/~cs230/amness/descartes.txt http://cs.wellesley.edu/~cs230/amness/popeye.html http://cs.wellesley.edu/~cs230/amness/seuss.txt
query> am green http://cs.wellesley.edu/~cs230/amness/seuss.txt
query> #contents // Note: the following results have been reformated to fit the page ./: SetVectorSorted[http://cs.wellesley.edu/~cs230/amness/dome.html] /a: SetVectorSorted[http://cs.wellesley.edu/~cs230/amness/, http://cs.wellesley.edu/~cs230/amness/dome.html, http://cs.wellesley.edu/~cs230/amness/popeye.html] /body: SetVectorSorted[http://cs.wellesley.edu/~cs230/amness/] /h1: SetVectorSorted[http://cs.wellesley.edu/~cs230/amness/] /html: SetVectorSorted[http://cs.wellesley.edu/~cs230/amness/] /title: SetVectorSorted[http://cs.wellesley.edu/~cs230/amness/] /ul: SetVectorSorted[http://cs.wellesley.edu/~cs230/amness/] a: SetVectorSorted[http://cs.wellesley.edu/~cs230/amness/, http://cs.wellesley.edu/~cs230/amness/dome.html, http://cs.wellesley.edu/~cs230/amness/popeye.html, http://cs.wellesley.edu/~cs230/amness/seuss.txt] also: SetVectorSorted[http://cs.wellesley.edu/~cs230/amness/popeye.html] am: SetVectorSorted[http://cs.wellesley.edu/~cs230/amness/, http://cs.wellesley.edu/~cs230/amness/descartes.txt, http://cs.wellesley.edu/~cs230/amness/popeye.html, http://cs.wellesley.edu/~cs230/amness/seuss.txt] amness: SetVectorSorted[http://cs.wellesley.edu/~cs230/amness/] and: SetVectorSorted[http://cs.wellesley.edu/~cs230/amness/seuss.txt] anywhere: SetVectorSorted[http://cs.wellesley.edu/~cs230/amness/seuss.txt] are: SetVectorSorted[http://cs.wellesley.edu/~cs230/amness/seuss.txt] back: SetVectorSorted[http://cs.wellesley.edu/~cs230/amness/dome.html] be: SetVectorSorted[http://cs.wellesley.edu/~cs230/amness/seuss.txt] boat: SetVectorSorted[http://cs.wellesley.edu/~cs230/amness/seuss.txt] body: SetVectorSorted[http://cs.wellesley.edu/~cs230/amness/] box: SetVectorSorted[http://cs.wellesley.edu/~cs230/amness/seuss.txt] car: SetVectorSorted[http://cs.wellesley.edu/~cs230/amness/seuss.txt] could: SetVectorSorted[http://cs.wellesley.edu/~cs230/amness/seuss.txt]
dark: SetVectorSorted[http://cs.wellesley.edu/~cs230/amness/seuss.txt] descartes: SetVectorSorted[http://cs.wellesley.edu/~cs230/amness/, http://cs.wellesley.edu/~cs230/amness/descartes.txt, http://cs.wellesley.edu/~cs230/amness/popeye.html] descartes.txt: SetVectorSorted[http://cs.wellesley.edu/~cs230/amness/] do: SetVectorSorted[http://cs.wellesley.edu/~cs230/amness/seuss.txt] dome: SetVectorSorted[http://cs.wellesley.edu/~cs230/amness/, http://cs.wellesley.edu/~cs230/amness/dome.html] dome.html: SetVectorSorted[http://cs.wellesley.edu/~cs230/amness/] eat: SetVectorSorted[http://cs.wellesley.edu/~cs230/amness/seuss.txt] eggs: SetVectorSorted[http://cs.wellesley.edu/~cs230/amness/seuss.txt] famous: SetVectorSorted[http://cs.wellesley.edu/~cs230/amness/] fox: SetVectorSorted[http://cs.wellesley.edu/~cs230/amness/seuss.txt] georgia: SetVectorSorted[http://cs.wellesley.edu/~cs230/amness/dome.html] goat: SetVectorSorted[http://cs.wellesley.edu/~cs230/amness/seuss.txt] good: SetVectorSorted[http://cs.wellesley.edu/~cs230/amness/seuss.txt] green: SetVectorSorted[http://cs.wellesley.edu/~cs230/amness/seuss.txt] h1: SetVectorSorted[http://cs.wellesley.edu/~cs230/amness/] ham: SetVectorSorted[http://cs.wellesley.edu/~cs230/amness/seuss.txt] here: SetVectorSorted[http://cs.wellesley.edu/~cs230/amness/seuss.txt] house: SetVectorSorted[http://cs.wellesley.edu/~cs230/amness/seuss.txt] href: SetVectorSorted[http://cs.wellesley.edu/~cs230/amness/, http://cs.wellesley.edu/~cs230/amness/dome.html, http://cs.wellesley.edu/~cs230/amness/popeye.html] html: SetVectorSorted[http://cs.wellesley.edu/~cs230/amness/] http://cs.wellesley.edu/~cs230/amness/descartes.txt: SetVectorSorted[http://cs.wellesley.edu/~cs230/amness/popeye.html] http://cs.wellesley.edu/~gdome: SetVectorSorted[http://cs.wellesley.edu/~cs230/amness/dome.html] i: SetVectorSorted[http://cs.wellesley.edu/~cs230/amness/, http://cs.wellesley.edu/~cs230/amness/descartes.txt, http://cs.wellesley.edu/~cs230/amness/dome.html, http://cs.wellesley.edu/~cs230/amness/popeye.html, http://cs.wellesley.edu/~cs230/amness/seuss.txt] iambic: SetVectorSorted[http://cs.wellesley.edu/~cs230/amness/dome.html] if: SetVectorSorted[http://cs.wellesley.edu/~cs230/amness/seuss.txt] in: SetVectorSorted[http://cs.wellesley.edu/~cs230/amness/seuss.txt] index: SetVectorSorted[http://cs.wellesley.edu/~cs230/amness/dome.html] let: SetVectorSorted[http://cs.wellesley.edu/~cs230/amness/seuss.txt] li: SetVectorSorted[http://cs.wellesley.edu/~cs230/amness/] like: SetVectorSorted[http://cs.wellesley.edu/~cs230/amness/seuss.txt] may: SetVectorSorted[http://cs.wellesley.edu/~cs230/amness/seuss.txt] me: SetVectorSorted[http://cs.wellesley.edu/~cs230/amness/seuss.txt] mouse: SetVectorSorted[http://cs.wellesley.edu/~cs230/amness/seuss.txt] not: SetVectorSorted[http://cs.wellesley.edu/~cs230/amness/seuss.txt] on: SetVectorSorted[http://cs.wellesley.edu/~cs230/amness/seuss.txt] or: SetVectorSorted[http://cs.wellesley.edu/~cs230/amness/seuss.txt] p: SetVectorSorted[http://cs.wellesley.edu/~cs230/amness/dome.html, http://cs.wellesley.edu/~cs230/amness/popeye.html] pentameter: SetVectorSorted[http://cs.wellesley.edu/~cs230/amness/dome.html] popeye: SetVectorSorted[http://cs.wellesley.edu/~cs230/amness/, http://cs.wellesley.edu/~cs230/amness/popeye.html] popeye.html: SetVectorSorted[http://cs.wellesley.edu/~cs230/amness/] quotes: SetVectorSorted[http://cs.wellesley.edu/~cs230/amness/] rain: SetVectorSorted[http://cs.wellesley.edu/~cs230/amness/seuss.txt] rene: SetVectorSorted[http://cs.wellesley.edu/~cs230/amness/descartes.txt] sam: SetVectorSorted[http://cs.wellesley.edu/~cs230/amness/seuss.txt] sam-i-am: SetVectorSorted[http://cs.wellesley.edu/~cs230/amness/seuss.txt] say: SetVectorSorted[http://cs.wellesley.edu/~cs230/amness/seuss.txt] see: SetVectorSorted[http://cs.wellesley.edu/~cs230/amness/popeye.html, http://cs.wellesley.edu/~cs230/amness/seuss.txt] seuss: SetVectorSorted[http://cs.wellesley.edu/~cs230/amness/] seuss.txt: SetVectorSorted[http://cs.wellesley.edu/~cs230/amness/]
Enqueueing Edge[url=http://cs.wellesley.edu/~gdome; distance=2] Indexing Edge[url=http://cs.wellesley.edu/~gdome; distance=2] Enqueueing Edge[url=http://cs.wellesley.edu; distance=3] Enqueueing Edge[url=http://cs.wellesley.edu/~gdome/list.html; distance=3] Enqueueing Edge[url=http://cs.wellesley.edu/~gdome/table.html; distance=3] Enqueueing Edge[url=http://cs.wellesley.edu/~gdome/cookies.html; distance=3] Indexing Edge[url=http://cs.wellesley.edu; distance=3] Indexing Edge[url=http://cs.wellesley.edu/~gdome/list.html; distance=3] Indexing Edge[url=http://cs.wellesley.edu/~gdome/table.html; distance=3] Indexing Edge[url=http://cs.wellesley.edu/~gdome/cookies.html; distance=3] query> chocolate chip http://cs.wellesley.edu/~gdome/cookies.html
query> img http://cs.wellesley.edu http://cs.wellesley.edu/~gdome http://cs.wellesley.edu/~gdome/list.html http://cs.wellesley.edu/~gdome/table.html
query> Thank you for using the indexing query system!
[fturbak@puma web-crawler] java WebCrawler 4 http://cs.wellesley.edu/~cs230/amness/ Indexing Edge[url=http://cs.wellesley.edu/~cs230/amness/; distance=0] Enqueueing Edge[url=http://cs.wellesley.edu/~cs230/amness/descartes.txt; distance=1] Enqueueing Edge[url=http://cs.wellesley.edu/~cs230/amness/seuss.txt; distance=1] Enqueueing Edge[url=http://cs.wellesley.edu/~cs230/amness/popeye.html; distance=1] Enqueueing Edge[url=http://cs.wellesley.edu/~cs230/amness/dome.html; distance=1] Indexing Edge[url=http://cs.wellesley.edu/~cs230/amness/descartes.txt; distance=1] Indexing Edge[url=http://cs.wellesley.edu/~cs230/amness/seuss.txt; distance=1] Indexing Edge[url=http://cs.wellesley.edu/~cs230/amness/popeye.html; distance=1] Indexing Edge[url=http://cs.wellesley.edu/~cs230/amness/dome.html; distance=1] Enqueueing Edge[url=http://cs.wellesley.edu/~gdome; distance=2] Indexing Edge[url=http://cs.wellesley.edu/~gdome; distance=2] Enqueueing Edge[url=http://cs.wellesley.edu; distance=3] Enqueueing Edge[url=http://cs.wellesley.edu/~gdome/list.html; distance=3] Enqueueing Edge[url=http://cs.wellesley.edu/~gdome/table.html; distance=3] Enqueueing Edge[url=http://cs.wellesley.edu/~gdome/cookies.html; distance=3] Indexing Edge[url=http://cs.wellesley.edu; distance=3] Enqueueing Edge[url=http://cs.wellesley.edu/cirque/invite.html; distance=4] Enqueueing Edge[url=http://cs.wellesley.edu/~cs/acm03; distance=4] Enqueueing Edge[url=http://cs.wellesley.edu/~cs/talks/jette; distance=4] Enqueueing Edge[url=http://cs.wellesley.edu/~cs/HessFellowship.html; distance=4] Enqueueing Edge[url=http://cs.wellesley.edu/~cs/HessFellowship.pdf; distance=4] Enqueueing Edge[url=http://cs.wellesley.edu/~cs/About/welcome.html; distance=4] Enqueueing Edge[url=http://cs.wellesley.edu/~cs/news; distance=4] Enqueueing Edge[url=http://cs.wellesley.edu/~cs/handbook.pdf; distance=4] Enqueueing Edge[url=http://cs.wellesley.edu/~cs/About/history.html; distance=4] Enqueueing Edge[url=http://cs.wellesley.edu/~cs/About/facilities.html; distance=4] Enqueueing Edge[url=http://www.wellesley.edu/Admission/admission/visiting.html; distance=4] Enqueueing Edge[url=http://cs.wellesley.edu/~cs/People/faculty.html; distance=4] Enqueueing Edge[url=http://cs.wellesley.edu/~cs/People/alumnae.html; distance=4] Enqueueing Edge[url=http://cs.wellesley.edu/~cs/Resources/tutoring.html; distance=4] Enqueueing Edge[url=http://cs.wellesley.edu/~cs/Resources/unix.html; distance=4] Enqueueing Edge[url=http://cs.wellesley.edu/~cs/Resources/work.html; distance=4] Enqueueing Edge[url=http://cs.wellesley.edu/%7Ecs/Resources/internships.html; distance=4] Enqueueing Edge[url=http://cs.wellesley.edu/~cs/Resources/gradprog.html; distance=4] Enqueueing Edge[url=http://cs.wellesley.edu/~cs/Resources/cswomen.html; distance=4] Enqueueing Edge[url=http://cs.wellesley.edu/~cs/Resources/csnews.html; distance=4] Enqueueing Edge[url=http://cs.wellesley.edu/~cs/Curriculum/Major.html; distance=4] Enqueueing Edge[url=http://www.wellesley.edu/MAS; distance=4] Enqueueing Edge[url=http://cs.wellesley.edu/~cs/Curriculum/whichCS1xx.html; distance=4]
Enqueueing Edge[url=http://cs.wellesley.edu/~cs/Curriculum/Courselistings.html; distance=4] Enqueueing Edge[url=http://cs.wellesley.edu/~cs/Curriculum/OnlineCourses.html; distance=4] Enqueueing Edge[url=http://cs.wellesley.edu/~cs/Curriculum/MITcourses.html; distance=4] Enqueueing Edge[url=http://cs.wellesley.edu/~cs/diagram.pdf; distance=4] Enqueueing Edge[url=http://cs.wellesley.edu/%7Ecs/Fall2006schedule.pdf; distance=4] Enqueueing Edge[url=http://cs.wellesley.edu/%7Ecs/Spring2007schedule.pdf; distance=4] Enqueueing Edge[url=http://cs.wellesley.edu/~cs/Research/research.html; distance=4] Enqueueing Edge[url=http://cs.wellesley.edu/~cs/Research/independ.html; distance=4] Enqueueing Edge[url=http://cs.wellesley.edu/~cs/Research/honors.html; distance=4] Enqueueing Edge[url=http://cs.wellesley.edu/cirque/; distance=4] Enqueueing Edge[url=http://cs.wellesley.edu/~cs/Activities/studentsem.html; distance=4] Enqueueing Edge[url=http://cs.wellesley.edu/~cs/Activities/cspanels.html; distance=4] Enqueueing Edge[url=http://cs.wellesley.edu/~cs/Activities/studentfun.html; distance=4] Enqueueing Edge[url=http://cs.wellesley.edu/%7Ecs/Activities/calendar07.html; distance=4] Enqueueing Edge[url=http://cs.wellesley.edu/~WAAM/; distance=4] Enqueueing Edge[url=http://cs.wellesley.edu/~wac/; distance=4] Indexing Edge[url=http://cs.wellesley.edu/~gdome/list.html; distance=3] Indexing Edge[url=http://cs.wellesley.edu/~gdome/table.html; distance=3] Enqueueing Edge[url=http://cs.wellesley.edu/~gdome/index.html; distance=4] Indexing Edge[url=http://cs.wellesley.edu/~gdome/cookies.html; distance=3] Enqueueing Edge[url=http://www.snopes2.com/business/consumer/cookie.htm; distance=4] Indexing Edge[url=http://cs.wellesley.edu/cirque/invite.html; distance=4] Indexing Edge[url=http://cs.wellesley.edu/~cs/acm03; distance=4] Indexing Edge[url=http://cs.wellesley.edu/~cs/talks/jette; distance=4] Indexing Edge[url=http://cs.wellesley.edu/~cs/HessFellowship.html; distance=4] Indexing Edge[url=http://cs.wellesley.edu/~cs/HessFellowship.pdf; distance=4] Indexing Edge[url=http://cs.wellesley.edu/~cs/About/welcome.html; distance=4] Indexing Edge[url=http://cs.wellesley.edu/~cs/news; distance=4] Indexing Edge[url=http://cs.wellesley.edu/~cs/handbook.pdf; distance=4] Indexing Edge[url=http://cs.wellesley.edu/~cs/About/history.html; distance=4] Indexing Edge[url=http://cs.wellesley.edu/~cs/About/facilities.html; distance=4] Indexing Edge[url=http://www.wellesley.edu/Admission/admission/visiting.html; distance=4] Indexing Edge[url=http://cs.wellesley.edu/~cs/People/faculty.html; distance=4] Indexing Edge[url=http://cs.wellesley.edu/~cs/People/alumnae.html; distance=4] Indexing Edge[url=http://cs.wellesley.edu/~cs/Resources/tutoring.html; distance=4] Indexing Edge[url=http://cs.wellesley.edu/~cs/Resources/unix.html; distance=4] Indexing Edge[url=http://cs.wellesley.edu/~cs/Resources/work.html; distance=4] Indexing Edge[url=http://cs.wellesley.edu/%7Ecs/Resources/internships.html; distance=4] Indexing Edge[url=http://cs.wellesley.edu/~cs/Resources/gradprog.html; distance=4] Indexing Edge[url=http://cs.wellesley.edu/~cs/Resources/cswomen.html; distance=4] Indexing Edge[url=http://cs.wellesley.edu/~cs/Resources/csnews.html; distance=4] Indexing Edge[url=http://cs.wellesley.edu/~cs/Curriculum/Major.html; distance=4] Indexing Edge[url=http://www.wellesley.edu/MAS; distance=4] Indexing Edge[url=http://cs.wellesley.edu/~cs/Curriculum/whichCS1xx.html; distance=4] Indexing Edge[url=http://cs.wellesley.edu/~cs/Curriculum/Courselistings.html; distance=4] Indexing Edge[url=http://cs.wellesley.edu/~cs/Curriculum/OnlineCourses.html; distance=4] Indexing Edge[url=http://cs.wellesley.edu/~cs/Curriculum/MITcourses.html; distance=4] Indexing Edge[url=http://cs.wellesley.edu/~cs/diagram.pdf; distance=4] Indexing Edge[url=http://cs.wellesley.edu/%7Ecs/Fall2006schedule.pdf; distance=4] Indexing Edge[url=http://cs.wellesley.edu/%7Ecs/Spring2007schedule.pdf; distance=4] Indexing Edge[url=http://cs.wellesley.edu/~cs/Research/research.html; distance=4] Indexing Edge[url=http://cs.wellesley.edu/~cs/Research/independ.html; distance=4] Indexing Edge[url=http://cs.wellesley.edu/~cs/Research/honors.html; distance=4] Indexing Edge[url=http://cs.wellesley.edu/cirque/; distance=4] Indexing Edge[url=http://cs.wellesley.edu/~cs/Activities/studentsem.html; distance=4] Indexing Edge[url=http://cs.wellesley.edu/~cs/Activities/cspanels.html; distance=4] Indexing Edge[url=http://cs.wellesley.edu/~cs/Activities/studentfun.html; distance=4] Indexing Edge[url=http://cs.wellesley.edu/%7Ecs/Activities/calendar07.html; distance=4] Indexing Edge[url=http://cs.wellesley.edu/~WAAM/; distance=4] Indexing Edge[url=http://cs.wellesley.edu/~wac/; distance=4] Indexing Edge[url=http://cs.wellesley.edu/~gdome/index.html; distance=4] Indexing Edge[url=http://www.snopes2.com/business/consumer/cookie.htm; distance=4]
Problem Set Header Page
Please make this the first page of your hardcopy submission.
CS230 Problem Set 4
Due 6pm Friday April 6
Names of Team Members:
Date & Time Submitted:
Collaborators (anyone you or your team collaborated with):
By signing below, I/we attest that I/we have followed the collaboration policy
as specified in the Course Information handout.
Signature(s):
In the Time column, please estimate the time you or your team spent on the parts of this problem
set. Team members should be working closely together, so it will be assumed that the time reported
is the time for each team member. Please try to be as accurate as possible; this information will
help me design future problem sets. I will fill out the Score column when grading your problem set.
Part Time Score
General Reading
Problem 1 [35]
Problem 2 [65]
Total
