嗨，我需要为我的WordLadder程序修复此OutOfMemoryError的帮助。基本上，我进入输入字梯文件的一半之后，该文件包含用于创建世界阶梯的开始和结束字，它会明显减慢速度并发生错误。我相信该错误是由于创建了多个堆栈而没有删除已使用的堆栈造成的。
该错误发生在getNewStacks方法的WordStack文件中的第74行：顾名思义，该方法应该获取新的堆栈。
下面是所有必需的文件：
字典txt：
https://drive.google.com/file/d/1vl6N4-3IYK86lGxmf0hqP7nX2e0BYrim/view?usp=sharing
输入txt：
https://drive.google.com/file/d/1ahHBL0ivqhC0zh24DCFnar03hxTt7Awc/view?usp=sharing
WordLadder主程序：
import java.io.File;
import java.io.FileNotFoundException;
import java.util.Scanner;
public class WordLadder {
public static void main(String args[]) throws FileNotFoundException {
Dictionary dictionary = new Dictionary(new File("dictionary.txt"));
Scanner scan = new Scanner(new File("input.txt"));
while (scan.hasNextLine()) {
String start = scan.next();
String stop = scan.next();
System.out.println(findLadder(start, stop, dictionary));
}
}
static String findLadder(String start, String end, Dictionary dictionary) {
if (!dictionary.contains(start) || !dictionary.contains(end)) {
return "No word ladder between \"" + start + "\" and \"" + end + "\".";
}
if (start.equals(end)) return start + " " + end;
LinkedList stackQueue = new LinkedList();
stackQueue.enqueue(new WordStack(start, end));
boolean continueSearch;
boolean success = false;
WordStack ladder = new WordStack();
do {
int queueSize = stackQueue.size();
continueSearch = false;
for (int stackIndex = 0; stackIndex < queueSize; stackIndex++) {
LinkedList newStacks = ((WordStack) stackQueue.dequeue()).getNewStacks(dictionary);
if (newStacks.size > 0) {
while (newStacks.size() > 0) {
WordStack next = (WordStack) newStacks.dequeue();
if (next.success()) {
success = true;
ladder = next;
break;
}
stackQueue.enqueue(next);
}
continueSearch = true;
}
if (success) break;
}
if (success) break;
} while (continueSearch);
if (success) return ladder.toString();
else return "No word ladder between \"" + start + "\" and \"" + end + "\".";
}
}
WordStack（错误行74的位置）：
public class WordStack {
LinkedList words;
String targetWord;
boolean success;
WordStack() {
words = new LinkedList();
targetWord = "";
success = false;
}
WordStack(LinkedList list, String target) {
words = list;
targetWord = target;
success = false;
}
WordStack(String startWord, String target) {
words = new LinkedList();
words.push(startWord);
targetWord = target;
success = false;
}
int size() {
return words.size();
}
void push(String word) {
words.push(word);
}
void add(String word) {
push(word);
}
String pop() {
if (size() < 1) return null;
return (String) words.pop();
}
String topWord() {
return (String) words.peek();
}
WordStack deepCopy() {
return new WordStack(words.hardCopy(), targetWord);
}
void markSuccess() {
success = true;
}
boolean success() {
return success;
}
boolean contains(String word) {
WordStack compare = deepCopy();
while (compare.size() > 0) {
if (word.equals(compare.pop())) return true;
}
return false;
}
LinkedList getNewStacks(Dictionary dictionary) {
LinkedList stacks = new LinkedList();
for (int letterPos = 0; letterPos < topWord().length(); letterPos++) {
for (char letter = 'a'; letter <= 'z'; letter++) {
String newWord = topWord().substring(0, letterPos) + letter + topWord().substring(letterPos + 1, topWord().length());
if (dictionary.contains(newWord) && !contains(newWord)) {
WordStack newStack = deepCopy();
newStack.push(newWord);
if (newWord.equals(targetWord)) newStack.markSuccess();
stacks.enqueue(newStack);
}
}
}
return stacks;
}
public String toString() {
String returnString = "";
for (int index = size() - 1; index >= 0; index--) {
returnString += (String) words.getPeek(index) + " ";
}
return returnString;
}
}
节点类：
public class Node {
public Object data;
Node next;
Node() {
data = null;
next = null;
}
Node(Object data) {
this.data = data;
next = null;
}
Object get() {
return data;
}
void set(Object data) {
this.data = data;
}
Node getNextPtr() {
return next;
}
void setNextPtr(Node next) {
this.next = next;
}
public String toString() {
return "" + data;
}
}
LinkedList：
public class LinkedList {
Node head;
Node tail;
int size;
LinkedList() {
head = null;
tail = null;
size = 0;
}
LinkedList hardCopy() {
LinkedList copy = new LinkedList();
if(size() < 1) return copy;
Node current = head;
while(current.getNextPtr() != null) {
copy.addEnd(current.get());
current = current.getNextPtr();
}
copy.addEnd(current.get());
return copy;
}
void iterateHead() {
head = head.getNextPtr();
size--;
}
void addEnd(Object newObj) {
enqueue(newObj);
}
void add(Object newObj) {
Node newNode = new Node(newObj);
if(size == 0) {
head = newNode;
}
else {
newNode.setNextPtr(head);
head = newNode;
}
size++;
}
Object peek() {
return head.get();
}
void push(Object newObj) {
add(newObj);
}
void enqueue(Object newObj) {
Node newNode = new Node(newObj);
if(size < 1) {
head = newNode;
tail = newNode;
} else {
tail.setNextPtr(newNode);
tail = newNode;
}
size++;
}
Object pop() {
Node pop = head;
if(size > 1) {
head = head.getNextPtr();
size--;
return pop.get();
}
else if(size == 1) {
size--;
head = null;
return pop.get();
}
else return null;
}
Object dequeue() {
if(size < 1) return null;
Node dequeueNode = head;
if(size > 1) {
iterateHead();
}
else {
head = null;
tail = null;
size--;
}
return dequeueNode.get();
}
int size() {
return size;
}
Object getPeek(int index) {
if(index >= size) return null;
Node current = head;
for(int i = 0; i < index; i++) {
current = current.getNextPtr();
}
Object data = current.get();
return data;
}
}
对于程序运行所需的代码量，我深表歉意。