只有在完成讨论解决方案第一部分的前一个query的历史记录后，才能回答此查询。
以下是我为 Part IIa 和 PartIIb 撰写的解决方案，在撰写 PartIIc 即toOcean()之前，我需要澄清一下方法
/* RunLengthEncoding.java */
package Project1;
/**
* The RunLengthEncoding class defines an object that run-length encodes an
* Ocean object. Descriptions of the methods you must implement appear below.
* They include constructors of the form
*
* public RunLengthEncoding(int i, int j, int starveTime);
* public RunLengthEncoding(int i, int j, int starveTime,
* int[] runTypes, int[] runLengths) {
* public RunLengthEncoding(Ocean ocean) {
*
* that create a run-length encoding of an Ocean having width i and height j,
* in which sharks starve after starveTime timesteps.
*
* The first constructor creates a run-length encoding of an Ocean in which
* every cell is empty. The second constructor creates a run-length encoding
* for which the runs are provided as parameters. The third constructor
* converts an Ocean object into a run-length encoding of that object.
*
* See the README file accompanying this project for additional details.
*/
class RunLengthEncoding {
/**
* Define any variables associated with a RunLengthEncoding object here.
* These variables MUST be private.
*/
private DList2 list;
private int sizeOfRun;
private int width;
private int height;
private int starveTime;
/**
* The following methods are required for Part II.
*/
/**
* RunLengthEncoding() (with three parameters) is a constructor that creates
* a run-length encoding of an empty ocean having width i and height j,
* in which sharks starve after starveTime timesteps.
* @param i is the width of the ocean.
* @param j is the height of the ocean.
* @param starveTime is the number of timesteps sharks survive without food.
*/
public RunLengthEncoding(int i, int j, int starveTime) {
this.list = new DList2();
this.list.insertFront(TypeAndSize.Species.EMPTY, i*j);
this.sizeOfRun = 1;
this.width = i;
this.height = j;
this.starveTime = starveTime;
}
/**
* RunLengthEncoding() (with five parameters) is a constructor that creates
* a run-length encoding of an ocean having width i and height j, in which
* sharks starve after starveTime timesteps. The runs of the run-length
* encoding are taken from two input arrays. Run i has length runLengths[i]
* and species runTypes[i].
* @param i is the width of the ocean.
* @param j is the height of the ocean.
* @param starveTime is the number of timesteps sharks survive without food.
* @param runTypes is an array that represents the species represented by
* each run. Each element of runTypes is Ocean.EMPTY, Ocean.FISH,
* or Ocean.SHARK. Any run of sharks is treated as a run of newborn
* sharks (which are equivalent to sharks that have just eaten).
* @param runLengths is an array that represents the length of each run.
* The sum of all elements of the runLengths array should be i * j.
*/
public RunLengthEncoding(int i, int j, int starveTime,
TypeAndSize.Species[] runTypes, int[] runLengths) {
this.list = new DList2();
this.sizeOfRun = 0;
this.width = i;
this.height = j;
this.starveTime = starveTime;
if(runTypes.length != runLengths.length){
System.out.println("lengths are unequal");
}else{
for(int index=0; index < runTypes.length; index++){
this.list.insertFront(runTypes[index], runLengths[index]);
this.sizeOfRun++;
}
}
}
/**
* restartRuns() and nextRun() are two methods that work together to return
* all the runs in the run-length encoding, one by one. Each time
* nextRun() is invoked, it returns a different run (represented as a
* TypeAndSize object), until every run has been returned. The first time
* nextRun() is invoked, it returns the first run in the encoding, which
* contains cell (0, 0). After every run has been returned, nextRun()
* returns null, which lets the calling program know that there are no more
* runs in the encoding.
*
* The restartRuns() method resets the enumeration, so that nextRun() will
* once again enumerate all the runs as if nextRun() were being invoked for
* the first time.
*
* (Note: Don't worry about what might happen if nextRun() is interleaved
* with addFish() or addShark(); it won't happen.)
*/
/**
* restartRuns() resets the enumeration as described above, so that
* nextRun() will enumerate all the runs from the beginning.
*/
public void restartRuns() {
this.sizeOfRun = 0;
}
/**
* nextRun() returns the next run in the enumeration, as described above.
* If the runs have been exhausted, it returns null. The return value is
* a TypeAndSize object, which is nothing more than a way to return two
* integers at once.
* @return the next run in the enumeration, represented by a TypeAndSize
* object.
*/
public TypeAndSize nextRun() {
TypeAndSize obj = null;
if(this.sizeOfRun > 0){
obj = this.list.nTh(this.sizeOfRun);
this.sizeOfRun--;
}
return obj;
}
}
==========
/* DList2.java */
package Project1;
/**
* A DList2 is a mutable doubly-linked list. Its implementation is
* circularly-linked and employs a sentinel (dummy) node at the sentinel
* of the list.
*/
class DList2 {
/**
* sentinel references the sentinel node.
*
* DO NOT CHANGE THE FOLLOWING FIELD DECLARATIONS.
*/
protected DListNode2 sentinel;
protected long size;
/* DList2 invariants:
* 1) sentinel != null.
* 2) For any DListNode2 x in a DList2, x.next != null.
* 3) For any DListNode2 x in a DList2, x.prev != null.
* 4) For any DListNode2 x in a DList2, if x.next == y, then y.prev == x.
* 5) For any DListNode2 x in a DList2, if x.prev == y, then y.next == x.
* 6) size is the number of DListNode2s, NOT COUNTING the sentinel
* (denoted by "sentinel"), that can be accessed from the sentinel by
* a sequence of "next" references.
*/
/**
* DList2() constructor for an empty DList2.
*/
public DList2() {
this.sentinel = new DListNode2();
this.sentinel.next = this.sentinel;
this.sentinel.prev = this.sentinel;
this.size = 0;
}
/**
* insertFront() inserts an object of type TypeAndSizeAndHungerAndStarveTime at the front of a DList2.
*/
void insertFront(TypeAndSize.Species runType, int runLength) {
DListNode2 newNode = new DListNode2(runType, runLength);
newNode.next = this.sentinel.next;
this.sentinel.next.prev = newNode;
this.sentinel.next = newNode;
this.sentinel.next.prev = this.sentinel;
this.size++;
}
/**
* nTh() returns the nTh node
* @param nTh
* @return
*/
TypeAndSize nTh(int nTh){
DListNode2 node = this.sentinel.prev;
int index = 1;
while(index < nTh ){
node = node.prev;
}
return node.runObject;
}
}
============================
/* DListNode2.java */
package Project1;
/**
* A DListNode2 is a node in a DList2 (doubly-linked list).
*/
class DListNode2 {
/**
* item references the item stored in the current node.
* prev references the previous node in the DList.
* next references the next node in the DList.
*
* DO NOT CHANGE THE FOLLOWING FIELD DECLARATIONS.
*/
TypeAndSize runObject;
DListNode2 prev;
DListNode2 next;
/**
* DListNode2() constructor.
*/
DListNode2() {
this.runObject = null;
this.prev = null;
this.next = null;
}
DListNode2(TypeAndSize.Species runType, int runLength) {
this.runObject = new TypeAndSize(runType, runLength);
this.prev = null;
this.next = null;
}
}
===================================
/* TypeAndSize.java */
/* DO NOT CHANGE THIS FILE. */
/* YOUR SUBMISSION MUST WORK CORRECTLY WITH _OUR_ COPY OF THIS FILE. */
package Project1;
/**
* Each TypeAndSize object represents a sequence of identical sharks, fish,
* or empty cells. TypeAndSizes are your way of telling the test program
* what runs appear in your run-length encoding. TypeAndSizes exist solely
* so that your program can return two integers at once: one representing
* the type (species) of a run, and the other representing the size of a run.
*
* TypeAndSize objects are not appropriate for representing your run-length
* encoding, because they do not represent the degree of hunger of a run of
* sharks.
*
* @author Jonathan Shewchuk
*/
class TypeAndSize {
Species type; // runType EMPTY, SHARK, or FISH
int size; // Number of cells in the run for that runType.
enum Species{EMPTY,SHARK,FISH}
/**
* Constructor for a TypeAndSize of specified species and run length.
* @param species is Ocean.EMPTY, Ocean.SHARK, or Ocean.FISH.
* @param runLength is the number of identical cells in this run.
* @return the newly constructed Critter.
*/
TypeAndSize(Species species, int runLength) {
if (species == null) {
System.out.println("TypeAndSize Error: Illegal species.");
System.exit(1);
}
if (runLength < 1) {
System.out.println("TypeAndSize Error: runLength must be at least 1.");
System.exit(1);
}
this.type = species;
this.size = runLength;
}
}
======================================
作为参考，link
中提供了完整的分配代码框架在给定的link中，以下段落说：
第二部分（c）：在RunLengthEncoding类中实现一个toOcean（）方法，该方法将游程编码转换为Ocean对象。要实现此目的，您需要在Ocean类中实现一个新的addShark（）方法，以便您可以指定添加到海洋中的每条鲨鱼的饥饿程度。通过这种方式，您可以将Ocean转换为游程编码并再次返回，而不会忘记每条鲨鱼的饥饿程度。
我的问题：
在RunLenghtEncoding() 5参数构造函数中编写的解决方案的 PartIIa 和 PartIIb 中，我没有捕获hungerLevel Shark属性由于方法评论中提到的原因 -
任何一群鲨鱼都被视为一群新生鲨鱼（相当于刚刚吃过的鲨鱼）。
我想知道，究竟toOcean()方法到底是什么意思。我不捕获hungerLevel runType的Shark。我想将海洋的压缩形式转换为现有的海洋＆＃39;或者＆＃39;新海洋＆＃39;？请帮助我，我被困在这里。
注意：这是2006年出版的自学课程。本课程没有导师。还建议我，如果这是讨论此类查询的正确位置
答案 0 :(得分：1)
它说
任何一群鲨鱼都被视为一群新生鲨鱼（相当于刚刚吃过的鲨鱼）。
因此，当您必须重新创建Ocean时，您可以将任意一组鲨鱼视为hungerLevel 0的鲨鱼。在第III部分中，您做必须保持然而，跟踪hungerLevel。但对于第二部分，他们暂时将其排除在外。