代写CS 2113编程、C/C++程序语言调试、代做Java设计编程

日期：2021-03-13 10:49

Project 1 | CS 2113 Software Engineering - Spring 2021

Project 1

There are two parts to this project, with two different deadlines. In part A, you will implement a hashtable

(hashmap) and linked list in C that is used in a spellcheck and boggle solver application. In part B, you will

complete the same data structures and applications using Java.

Preliminaries

Github Classroom links

Part A: https://classroom.github.com/a/fxDdTKFg (C Portion)

Part B: https://classroom.github.com/a/0QShWEWQ (Java Portion)

Test Script

To help you complete this project, each part is provided with a test script. The script is not designed to be

comprehensive, and you will graded based on a larger array of tests. To execute the test script, run it from

anywhere within the lab directory.

./test.sh

Note that when executing the test script using replit, due to using valgrind, it may take upwards of 5 minutes to

complete! So you are better served developing some tests on your own rather than relying on the test script.

Compiling your code:

Part A

For part A (C implementation), we have provided you with a Makefile . You can compile the spellchecker or

boggle solver by typing:

make spellcheck

make onePlayerBoggle

If you want to compile everything at once, simply type make . This will produce a number of additional .o files

(or object files), which are compiled C files that are not yet assembled. Do not add these to your repository as

they get overridden on every compilation.

To clean up your repository, you can use make clean command.

Part B

For part B (Java implementation), you should compile using javac .

CS2113SoftwareEngineering-Spring2021

2/24/2021 Project 1 | CS 2113 Software Engineering - Spring 2021

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javac SpellChecker

javac OnePlayerBoggle

You should not add your class files ( .class ) to the repository.

Development Environments

You can complete both parts using replit, if you so desire. For part A you will find that valgrind will run much

faster using a local Ubuntu installation, either via WSL or in a virtual machine — this is our recommended

development choice.

For part B, you may use replit, or you could develop your code in IntelliJ. One benefit of IntelliJ is that you can use

its built in debugger, which is extremely helpful.

Data Structure Implementations

In both parts of the project, you will be implementing two basic data structures: a Linked List and a Hash Table (or

Hashmap).

Linked List

The Linked List you will complete only requires forward pointers on its nodes, and only the push() operation, that

is, put a new node on the front of the list. Each node in the list stores a string value. There is no need for the list to

be generic.

Hashmap

The Hashmap data structure is simply a membership Hash Table — unlike a truly generic Hashmap that stores key,

value pairs, this table returns true if an items is stored in the data structure and false otherwise. Put another

way, itʼs a Hashmap that maps a value to true. The Hashmap you will implement only needs to store strings. It has

the following member functions:

add(string) -> void : add a string to the hashmap

check(string) -> bool : check to see if a string is in the hashamp, return true if present, else false.

The Hashmap should be implemented as a hash table with separate chaining. You may recall from your data

structures class, this means that when two elements collide at an index, you add the item on to that spot, using say

Linked List.

Following that model, your Hashmap should have an array (or buckets) of Linked Lists. After achieving the hash

value for a given string (modulo the range of buckets), you push that string onto the Linked List at that index

associated with the hash value. Critically, the performance of the Hashmap depends on the length of the lists of

each bucket — if the lists get too long, then the look up operation could become O(n)!

The load on a hash table is defined as the number of items stored in the table divided by the number of buckets.

High loads means longer lists at each bucket and worse performance. To keep performance steady, once the load

reaches 0.75, you have to resize the hash table by doubling the number of buckets and reinserting all the items into

their new hash locations. YOU MUST IMPLEMENT A RESIZE ROUTINE – YOU CANNOT SIMPLY SET YOUR

NUMBER OF BUCKETS TO A LARGE VALUE!!

2/24/2021 Project 1 | CS 2113 Software Engineering - Spring 2021

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Part (A) (C Implementation) (70 Points)

Github

Data Structure Implementation

The crucial part of this project is the data structure implementations. In C, you typically divide your data structures

between a header file (a .h file) and a source file (a .c file). The header file contains the structure and function

definitions, while the source file contains their implementations. You will primarily work with the source files ( .c ).

Linked List

As you can see the llist.h , the Linked List defines two strucures:

//node type stored in lists

typedef struct ll_node{

struct ll_node * next; //next node in list

char * val; //string value stored in list

} ll_node_t;

//list_t struct to store a list

typedef struct{

ll_node_t * head; //pointer to the node at the head of the list

int size; //the number of nodes in the list

} llist_t;

The ``ll_node_t is a node within the linked list, storing the value (a char * string) and a

pointer to the next node. The llist_t` is a structure representation of the list, storing a pointer to the head of

the list and itʼs current size (number of nodes.

There are three functions that operate over lists, described below. In llist.c you implement these methods.

// Return a newly initialized, empty linked list

llist_t * ll_init();

//delete/deallocate a linked list

void ll_delete(llist_t * ll);

//insert the string v (duplicated vis strdup!) onto the front of the list

void ll_push(llist_t * ll, char * s);

Hash Map

The hashmap data strcucture is defined in hashmap.h and you will implemented in hashmap.c . The header file

containing the structure and functions can be found below (with comments).

#define HM_INIT_NUM_BUCKETS 16

#define HM_MAX_LOAD 0.75

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In the C file you will implement a non-public (as in not in the header file) function _resize()

void _resize(hashmap_t * hm)

which is called when the load is greater than 0.75.

Spellchecker

To help test your Hashmap and Linked List implementation, weʼve provided a simple interactive spellchecker

program that allows the user to type phrases (without punctuation) and it will spellcheck it. Hereʼs some sample

inputs and outputs, along with the compilation.

typedef struct{

llist_t ** buckets; //array of `buckets` each pointing to a list_t (see list.h)

int num_buckets; //how many buckets, or lenght of the bucket array (should always be a power of 2

int size; //how many items stored

} hashmap_t;

//initliaze a hashmap with INITIAL_BUCKETS number of buckets

hashmap_t * hm_init();

//delete/deallocate the hashmap

void hm_delete(hashmap_t * hm);

//add a string value to the hashmap

void hm_add(hashmap_t * hm, char * v);

//see if a string value is in the hashmap

bool hm_check(hashmap_t * hm, char * v);

$ make

gcc -Wall -Wno-unused-variable -g -c -o hashmap.o hashmap.c

gcc -Wall -Wno-unused-variable -g -c -o llist.o llist.c

gcc -Wall -Wno-unused-variable -g -o spellcheck spellcheck.c hashmap.o llist.o -lreadline -lm

gcc -Wall -Wno-unused-variable -g -c -o boggle.o boggle.c

gcc -Wall -Wno-unused-variable -g -o onePlayerBoggle onePlayerBoggle.c boggle.o hashmap.o llist.o -

$ ./spellcheck

ERROR: require dictionary file

$ ./spellcheck dictionary.txt

spellcheck > spellcheck all these words at once

SPELLCHECK -> not a word

ALL -> WORD

THESE -> WORD

WORDS -> WORD

AT -> WORD

ONCE -> WORD

spellcheck > or

OR -> WORD

spellcheck > one

ONE -> WORD

2/24/2021 Project 1 | CS 2113 Software Engineering - Spring 2021

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Boggle Solver

Now that youʼre Hash Map and Linked List are working, letʼs use them to do something a bit more interesting —

finding all the words on a boggle board!

The boggle game structure and functions are defined in boggle.h and you will do most of your work in

boggle.c . A boggle instance is defined as a 5x5 grid of dice, where each dice displays a different character.

#define BOGGLE_DIMENSION 5

typedef struct {

char board[BOGGLE_DIMENSION][BOGGLE_DIMENSION]; //the boggle board

hashmap_t * dict; //dictionary mapping

} boggle_t;

When printed the board looks like

.-----------.

| S N T A Y |

| W N T E I |

| N QuI H I |

| N F O S U |

| E E H N L |

'-----------'

The goal is to find as many words (at least three letters long) by traversing from one dice to another in all

directions (left, right, up, down, and diagonal) without using a dice more than once. So for example QUIT is a

word found on the board, and so is QUITE . (You get a free ‘uʼ for your ‘Qʼ.)

A number of functions are implemented and provided for you in boggle.c , your main work will be completing the

bg_all_words() function, which will search the boggle board for all words 3 letters to 8 letters in length.

spellcheck > at

AT -> WORD

spellcheck > a

A -> WORD

spellcheck > time

TIME -> WORD

spellcheck > this adfasdfasdf is not a word

THIS -> WORD

ADFASDFASDF -> not a word

IS -> WORD

NOT -> WORD

A -> WORD

WORD -> WORD

spellcheck > nor !!!

NOR -> WORD

!!! -> not a word

spellcheck >

$ # type ^D to insert EOF to exit (or ^C)

2/24/2021 Project 1 | CS 2113 Software Engineering - Spring 2021

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This is a recursive method that will explore outwards from a letter tile using depth first search. The idea is that

you start a tile, like Qu and then try all neighbors (via a recursive call), outward, adding letters as you go and

checking to see if you found a word. At somepoint you either search off the board or descended too far (checking

a 9 letter word), and the recursion returns to explore another path. An algorithmic description is provided in a

comment within boggle.c — see there for more details.

Once you complete, you can run the onePlayerBoggle program at a given random seed, like below:

aaviv@cs2113-vm:~/project-1a-inst$ ./onePlayerBoggle dictionary.txt 100

Total Points: 205

Note that the words are not alphabetical because hash tables are not ordered data structures.

Part (B) (Java Implementation) (30 Points)

In the second part of this project, you will implement your Hash Map and Linked List in Java using Object Oriented

Principles. Hereʼs a quick guide to the source files found in this part. There are comments throughout and TODO

marked where you should do your implementation. The same functions/methods on each of the objects as

described in part A still apply, but now in Java.

LList.java : Java class for implementing a Linked List. Additionally, you need to make your Linked List

iterable, such that it can be used in for(String s : list) — see details in the source file.

HMap.java : Java class for implementing your Hash Map. Additionally, you need to implement a

traversal() method that returns a LList of all the values stored in the HMap.

SpellCheck.java : Java class with a main method for testing your Lined List and HMap. Run it like so:

java SpellCheck dictionary.txt

Boggle.java : Java class representing a Boggle instance. You (again) will need to complete the

allWords() method.

OnePlayerBoggle.java : Java class with a main method for performing a boggle solve. Run it like so:

java OnePlayerBoggle dictionary.txt [seed]

where [seed] is replaced with the seed for the random number generator. If omitted, a random seed is

used.

Hereʼs some sample output of running the boggle solver with seed 100. Note that Java uses a different random

number generator, so it is different than above.

Total Points: 185

Bonus (part B) (up to +25 points)

Create a new branch in your repository called optimized and work within that branch — do not

make these changes on your main branch otherwise it may affect your grading of part B. Once

complete push this branch to the github and also open a issue with the title “BONUS Submission

Optimized”

Modify your HMap and LList implementations (or implement/use other data structures from Java stdlib) in part B,

as well as the boggle routines such that you optimize performance as best you can. The top 5 fastest boggle

solvers in the class will win recognition and bonus points:

1st place: 25 points

2nd/3rd place: 15 points

4th/5th place: 10 points

Some ideas/hints for optimizing your performance:

There are some combinations of letters that can never form words

You could avoid resizing your hashtable if you know how many items your were storing?

I/O is a drag

Java stdlib can be fast, but specialized data structures can be faster — depends on what your doing

Try running with java -Xss2m to profile your implementation

You can test your speed of your java solver by running it with

time java OnePlayerBoggle dictionary.txt

and look at the real time output.

Bonus (part B) (10 points)

Create a new branch in your repository called ordered and work within that branch — do not

make these changes on your main branch otherwise it may affect your grading of part B. Once

complete push this branch to the github and also open a issue with the title “BONUS Submission

Ordered”

Use Java standard library to replace/modify/etc your Hash Map and Linked List implementations with different data

structures provided there such that the output of the words from the OnePlayerBoggle are in sorted order.