This assignment contains 3 parts. You need to download the files provided and complete the ollowing 13 files: - Except for the MyDoublyLinkedlist.java, where a starting file is provided, you have to create all the above classes from scratch. For the first part, you will write several classes to implement different data structures. [5 points] Write an interface MyList E> with a generic element type E. The MyList E> interface extends the Iterable interface. The MyList interface has the following public methods: - A getsize method that returns an int indicating the number of elements in the list. - A isEmpty method that returns a boolean indicating whether the list is empty. - An add method that appends the specified element to the end of this list and does not return anything. - A clear method that removes all of the elements from this list and does not return anything. - A remove method that removes the last element from the list and returns it. [5 points] Write an abstract class MyLinkedList E> with a generic type E and implements MyList . The MyLinkedList E class has the following protected field: - A int indicating the size of the list. The class must also implement the public methods getsize and isEmpty as specified by the documentation of the interface MyList E. [15 points] Complete the MyDoublyLinkedList E class (provided) as a doubly linked-list of generic type E. Inside the file provided you can find: - A private class called DLLIterator and a method iterator returning a DLLIterator object. This DLLIterator class implements the Iterator interface (from java. util. Iterator) which allows the user to iterate over the list. DO NOT modify anything from the DLLIterator class or the iterator method; otherwise, your program will fail the testers. - A private class called DNode. The DNode class contains three private fields: - An E named element indicating the element stored in the node - A DNode named next indicating the next node in the list. - A DNode named prev indicating the previous node in the list. - The MyDoublyLinkedList E> class has the following private fields: - A DNode named head indicating the head of the list - A DNode named tail indicating the tail of the list It is up to you to do the following: - Make sure the class MyDoublyLinkedList E> extends the MyLinkedList E> class. - Implement the public methods add, remove, and clear as specified in the documentation of the interface MyList. - Add the following public methods to the MyDoublyLinkedList E> class: - An addFirst and an addLast method which takes input as an object of the generic type E and adds the element as the first/last element of the list. These methods do not return anything. - A removeFirst and a removelast method which removes the first/last node from the list and returns the element. The method should throw a NoSuchElementException if the list is empty. - A peekFirst and a peekLast method which returns the first/last element without removing it from the list. The method should throw a NoSuchElementException if the list is empty. - An equals method that takes an Object as an input; the method returns true if all elements in the list are considered to be equal and false otherwise. You are free to add any additional private methods and/or fields to either MyDoublyLinkedList E> or DNode if you think this can help you with the implementation. Please note that, as specified in the general instructions, you are NOT allowed to add any field of type array. [5 points] Write a class MyStack. The MyStack class has the following private fields: - A MyDoublyLinkedList E> to store the elements of the stack. The class must also have the following public methods: - A constructor that takes no inputs and creates an empty stack. - A push method that takes an input of type E and adds the input to the top of the stack. - A pop method that removes the top of the stack and returns it. The method should throw a NoSuchElementException if the stack is empty. - A peek method that returns the element at the top of the stack without removing it. The method should throw a NoSuchElementException if the stack is empty. - A isEmpty method that returns true if the stack is empty and false otherwise. - A clear method that clears the stack (i.e. removes all the elements from the stack). - A getSize method that returns the number of elements in the stack. 5 points] Write a class Myqueue E>. The MyQueue E class has the following private fields: - A MyDoublyLinkedList E to store the elements of the quene. The class must also have the following public methods: - A constructor that takes no inputs and creates an empty queue. - A enqueue method that takes an input of type E and adds it to the back of the queue. - A dequeue method that removes the first element from the front of the queue and returns it. The method should throw a NoSuchElementException if the queue is empty. - An isEmpty method that returns true if the queue is empty and false otherwise. - A clear method that clears the queue (i.e. removes all the elements from the queue). - An equals method that takes as input an 0bject and returns true if the input is another queue with equal elements, and false otherwise. PART - II: Information Parsing with Stacks (35 points) In PART-II, you will decode and parse strings that contain compressed information. [7 points] Write a Position class as a representation of a point (x,y) on a 2D map as the figure below. The origin (0,0) is located at the top-left corner of the map. The Position class has the following private fields: - An int indicating the x-coordinate on the map - An int indicating the y-coordinate on the map The Position class must also have the following public methods: - A constructor that takes two int as inputs indicating the x - and y-coordinates on a map, in this order. The constructor uses the inputs to initialize the corresponding fields. - A constructor that takes a Position as input and initializes the fields with the corresponding input. This type of constructors are called copy constructors. They are used to create duplicates of existing instances of the class. - A reset method that takes two int as inputs indicating the x - and y-coordinates on a map. The method uses the inputs to resets the corresponding fields. - A reset method that takes Position as input and resets the corresponding fields using the values of those of the input object. - A static method called getDistance that takes two Position objects as input and returns the absolute distance between them in terms of the x - and y-coordinates. For example, the distance between two Position objects (2,3) and (3,5) is 3 (i.e. 23 +35). - A get X and a getY method that return the values of the corresponding fields. - A moveWest method that decrements the x-coordinate by 1. - A moveEast method that increments the x-coordinate by 1 . - A moveNorth method that decrements the y-coordinate by 1. - A moveSouth method that increments the y-coordinate by 1. - An equals method which takes as input an Dbject and returns true if the input matches this in type, x-coordinate, and y-coordinate. Otherwise, the method returns false. [13 points] Write a Targetqueue class that extends from MyQueue>. The TargetQueue class is designed to store a list of Position objects. The TargetQueue can parse a string and store the information as a queue. For example, given a string " (1,2),(3,4). (5,6). ", the input should be parsed into a queue of 3 positions shown in the figure below: Figure 1: A queue of positions after parsing " (1,2)(3,4)(5,6) " Note that, the input string has this strict format (x,y). The x - and y-coordinates are enclosed by a left and a right parenthesis separated by a comma, and two positions must be separated by a period. The TargetQueue class has the following private fields: - A MyStack to help with parsing a string containing information about the positions. The TargetQueue class must also have the following public methods: - A constructor that takes no input. The constructor should invoke the constructor of the superclass and initialize its fields. - A clear method that clears this queue and its stack field. - An addTargets method that takes input as a String and parses it into a queue of Positions. The method should throw an IllegalArgumentException if the syntax of the input is invalid. It can be useful for this method to have a local String variable to store the numbers contained in the input string. I will refer to this variable as num. To check the validity of the syntax and parse out the information regarding the positions, we need to iterate through every character in the input string. - if the character is a left parenthesis, the stack and num should both be empty. If so, push "(" onto the stack. - if the character is a digit, append the digit to num. - if the character is a comma, check if num is a valid integer. If num is empty, we must have read a comma before the x-coordinate, which is a syntax error. Otherwise, push num and "," onto the stack, in exactly this order. Finally, reset num. - if the character is a right parenthesis * the stack should contain 3 elements with exactly the order a comma, an integer, and a left parenthesis from the top. If the order is not correct or any of the elements are missing, the input string has a syntax error. 7 * num should be an integer representing the y-coordinate. If num is empty, we must have reached the right parenthesis without finding a y-coordinate, which is a syntax error. * If the syntax is correct, add the xy coordinate as a Position object onto the quene and reset num. - if the character is a period, we must have reached the end of expression for a particular position. If the syntax is correct, the stack and num should both be empty. Otherwise, this is another syntax error. Note that, these are the minimum cases of syntax errors that you should take care of. There might be more edge cases that do not get detected by the instructions above. It would be your job to find them and throw exceptions when needed. [2 points] Write an enumeration Direction. An enumeration in java is a special data type that represents a fixed set of constants. Defining and using enumerations will make your code a bit more readable. The syntax is as follows: Inside a file called Direction. java you should define an enumeration called Direction that represents the directions. The enumeration Direction has four values NORTH, SDUTH, WEST, EAST. [13 points] Write a ActionQueue class that extends Myqueue. The Actionqueue class decodes a string that contains compressed information on directions into a queue of Direction objects. The input strings are encoded in the form K[D] which indicates that the direction(s) D is repeated K times. K should be a positive number. D should contain characters ' N ', ' S ', ' W ', ' E ' that represent directions. Specifically, ' N ' stands for NORTH, ' S ' stands for SDUTH, ' W ' stands for WEST, and 'E' stands for EAST. Table 1 contains some examples of encoded strings and their decoded values: Note that, implementing this class is meant to be a bit more challenging, and hence, the implementation details are omitted. You will need to understand and analyze the task at hand and decide how to go about implementing such class. Table 1: Examples of encoded and decoded directions It is up to you to decide how many, and what type of private fields you might need for this class. Different implementations are possible. Remeber to exploit the properties of stacks to help you parse strings. The Actionqueue class must have the following public methods: - A constructor that takes no input and takes care of initializing whichever field(s) you have added. - A clear method that removes all items from this queue (and possibly clears the field(s)) - A loadFromEncodedString method that takes input as a String of an encoded message and converts it into a queue of Direction. Similar to the TargetQueue, the method should throw an IllegalArgumentException if the syntax of the input is invalid. It is up to you to figure out when and where to throw exception, or otherwise to translate the string into the corresponding queue of Directions. I suggest you start by focusing on how to correctly parse very simple strings like 3[N]. Then move onto correctly parsing sequences of simple strings like 2[N]3[W] or more complicated strings such as 3[NE]. Finally, try to solve the problem of parsing nested strings such as 3[2[N]2[E]]. Please do not focus on getting this part to work to perfection before moving onto Part III of the assignment. You do not need this to be working to complete what comes next. In fact, you can still get a very high mark even if this part is only partially working. Make sure to use your time wisely! PART - III: Caterpillar Game (30 points) In PART-III, you will write a small caterpillar game. The figure below shows a 2D map with a caterpillar (blue) and food (red). The caterpillar can move around in this 2D map. Whenever the caterpillar's head reaches the food, it can "eat" the food and grow one cell bigger. You will write a small program that moves the caterpillar, and the final goal is to eat everything on the map. Figure 2: The caterpillar (blue) and the food (red) in a 2D map. The xy-coordinate of the top-left corner is (0,0), and the xy-coordinate of the bottom-right corner is (15,15). [ 3 points] Write a Region class that represents a 2D world. The Region class has the following private fields: - A int indicating the minimum x-position - A int indicating the minimum y-position - A int indicating the maximum x-position - A int indicating the maximum y-position The Region class has the following public methods: - A constructors with 4 inputs as int which indicates minimum x position, minimum y position, maximum x position, and maximum y position (in exactly this order). - A contains method that takes an input as Position. The method returns true if the position is within the range of the Region and returns false otherwise. For example, if the range is x[0,5],y[3,6], then the minimum x and y positions are 0 and 3 , and the maximum x and y positions are 5 and 6 (inclusive). The method contains should return true if the input is (0,6) and return false if the input is (10,11). [10 points] Write a Caterpillar class that extends MyDoublyLinkedList . A Caterpillar is represented as a MyDoublyLinkedList that completely determines the positions of the body of a caterpillar within a 2D map. The Caterpillar class must have the following public methods: - A constructor that takes no input and sets the initial state of the caterpillar at the beginning of a game. When the game starts, the initial size of the caterpillar should be 1 and its initial position is at (7,7). - A getHead method that returns a Position object representing the head position of the caterpillar. - An eat method that takes as input a Position and adds the input to the front of the list, making this be the new position for the head of the caterpillar. If the input position is not orthogonally adjacent to the current head position, throw an IllegalArgumentException. - A move method that takes as input a Position, adds the input to the front of the list, and removes one element from the back of the list. If the input position is not adjacent to the current head position, throw an IllegalArgumentException. - A selfCollision method that takes as input a Position and returns true if the input overlaps with one of the body parts, and returns false otherwise. [2 points] Write a GameState enumeration. The GameState enumeration contains the following labels: WALL_COLLISION, SELF_COLLISION, NO_MORE_ACTION, EAT, MOVE, DONE. [15 points] Write a World class. The World class should have the following private fields (You can add more private fields whenever fits): - A Caterpillar that represents the caterpillar. - A Position that indicates the current food position. - A Region that represents the 2D map where the caterpillar can move. - A Actionqueue that stores a list of actions to take for the caterpillar. - A TargetQueue that stores a list of food positions that the caterpillar should travel to. - A GameState which indicates the current state of the game. The World class must also have the following public methods: - A constructor that takes two input arguments; the first argument is a TargetQueue and the second argument an ActionQueue. The constructor uses the inputs to initialize the appropriate fields. The Region of the game is set as x[0,15],y[0,15], and the caterpillar is initialized with its initial state (its size is 1 , and it is positioned at (7,7) ). Before the game starts, dequene the food position from the TargetQueue, and set the GameState to MDVE. You can assume that the game will start with at least one food to be eaten by the caterpillar. A step method that makes a step in the game. Here are the procedures: - First, take the next heading direction from the ActionQueue. If the Actionqueue is empty, set the GameState to NO_MORE_ACTION. - Second, if the GameState is not MOVE or EAT, return. - Then, get the current head position of the caterpillar and calculate the next head position assuming it is moving according to the heading direction. For example, if the head position of the caterpillar is (5,7) and the direction is EAST, the next position will be (6,7). Depending on the next position calculated above, You will need to handle the following scenarios: * If moving to the next position will result in the caterpillar moving out of the map, set the GameState to WALL_COLLISION. * If moving to the next position will result in a self-collision of the caterpillar, set the GameState to SELF_COLLISION. * If the food is located at the next position, the caterpillar can "eat" it. If there is not more food on the TargetQueue, the caterpillar must have eaten everything, and we can set the GameState to DONE. Otherwise, dequeue the next food position from the TargetQueue and set the GameState to EAT. * Otherwise, move the caterpillar to the next position and set the GameState to MOVE. - A getState method that returns the current state of the game as a GameState. - A getCaterpillar method that returns the caterpillar as a Caterpillar object. - A getFood method that returns the food position as a Position object. - An isRunning method that returns true if the game is still running (MOVE or EAT) or false if the game is over