0
對不起，如果這是一個非常長的代碼，但唯一的問題是LinkedList類中的remove（）方法，並且我一直在這個代碼上掙扎幾個小時，似乎無法找到解決方案。每當我輸入地址456的主要方法，而不是打印爲什麼我的自定義LinkedList中的remove（）方法無法正常工作？
0+6+5+4
RESULT 15
我不斷獲取
0+6+6+4
RESULT 16
這意味着要麼刪除（）或插入（）方法出了問題，但是當我檢查insert（）方法的輸入5在必要時被正確插入。所以我想知道remove（）方法的哪一部分出錯了，我該如何解決它。謝謝。
這些是接口。
接口堆棧。
package ds.stack;
public interface Stack<E> {
/*
* Removes all of the elements in this stack.
*/
public void clear();
/*
* Pushes an item onto the top of this stack.
*
* @param item
* the item to be pushed onto this stack
*/
public void push(E item);
/**
* Removes the item at the top of this stack and returns that item as the
* value of this method.
*
* @return the item at the top of this stack, or null if this stack is empty
*/
public E pop();
/**
* Returns the number of elements in this stack.
*
* @return the number of elements in this stack
*/
public int length();
/**
* Returns true if this stack contains no elements.
*
* @return true if this stack contains no elements
*/
public boolean isEmpty();
}
接口列表。
package ds.list;
public interface List<E> {
/**
* Removes all of the elements from this list.
*/
public void clear();
/**
* Inserts the specified element at the specified position in this list.
*
* @param pos
* index at which the specified element is to be inserted
* @param item
* element to be inserted
*/
public void insert(int pos, E item);
/**
* Removes the element at the specified position in this list. Shifts any
* subsequent elements to the left (subtracts one from their indices).
* Returns the element that was removed from the list.
*
* @param pos
* the index of the element to be removed
* @return the element previously at the specified position
*/
public E remove(int pos);
/**
* Returns the number of elements in this list.
*
* @return the number of elements in this list.
*/
public int length();
/**
* Returns the element at the specified position in this list.
*
* @param pos
* index of the element to return
* @return the element at the specified position in this list
*/
public E getValue(int pos);
}
這裏是我的LinkedList類
package ds.list;
public class LinkedList<E> implements List<E> {
private E element;
private LinkedList<E> next;
private LinkedList<E> head;
private LinkedList<E> tail;
private LinkedList<E> curr;
public int cnt=0; //length of the list
/*
* constructors below
*/
public LinkedList() { //The very initial constructor
curr = tail = head = this;
}
public LinkedList(LinkedList<E> nextval) { //when you start making more bundles
next = nextval;
}
public void setNext(LinkedList<E> nextval) {
next = nextval;
}
public void goNext() {
curr = next;
} // curr becomes the next bundle
public void setValue(E item) {
element = item;
}
@Override
public void clear() {
tail = head = new LinkedList<E>();
next = null;
cnt = 0;
}
@Override
public void insert(int pos, E item) {
if(pos<0||pos>cnt+1) {
return;
}
if(pos==0) {
curr = head;
head = new LinkedList<E>(curr);
curr = head;
curr.setValue(item);
}
curr = head;
for(int i=0;i<pos-1;i++) {
goNext();
} //curr points right before the index of pos
LinkedList<E> temp = curr.next;
curr.setNext(new LinkedList<E>(temp));
curr.goNext();
curr.setValue(item);
cnt++;
}
@Override
public E remove(int pos) {
if(pos<0||pos>cnt)
return null;
curr = head;
if(cnt==1) {
E it = element;
curr = head = tail = null;
cnt--;
return it;
}
for(int i=0;i<pos-1;i++) {
goNext();
}
E it = next.element;
curr.setNext(next.next);
cnt--;
return it;
}
@Override
public int length() {
return cnt;
}
@Override
public E getValue(int pos) {
if(pos<0||pos>cnt)
return null;
curr = head;
for(int i=0;i<pos-1;i++) {
goNext();
}
return next.element;
}
}
，這是我LinkedStack類，利用LinkedList類
package ds.stack;
import ds.list.LinkedList;
public class LinkedStack<E> implements Stack<E> {
private LinkedList<E> stack = new LinkedList<E>();
@Override
public void clear() {
stack.clear();
}
@Override
public void push(E item) {
if(stack.cnt == 0) {
stack.setValue(item);
stack.cnt++;
return;
}
stack.insert(stack.length(),item);
}
@Override
public E pop() {
if(stack.length()==0) {
return null;
}
else {
return stack.remove(stack.length()-1);
}
}
@Override
public int length() {
return stack.length();
}
@Override
public boolean isEmpty() {
if(stack.length()==0)
return true;
return false;
}
}
那麼這是一個使用LinkedStack類
我BabyCalculator類package ds.test;
import ds.stack.LinkedStack;
import ds.stack.Stack;
public class BabyCalculator {
Stack<Character> stack = new LinkedStack<Character>();
private int value=0;
public int murmurAdd(String polynomial) {
char[] charPol=polynomial.toCharArray();
int count=0;
for(int i=0;i<polynomial.length();i++) {
if(!(Character.isDigit(charPol[i])))
count++;
} // This counts the total number of (and)s.
int numOf=count/2;
if (numOf==0) {
for(int i=0;i<polynomial.length();i++) {
stack.push(charPol[i]);
}
}
else {
for(int i=0;i<numOf;i++) {
int num1=0, num2 = 0; //will become the index of last (and first)
for(int j=0;j<polynomial.length();j++) {
if(charPol[j]=='(')
num1 = j;
if(charPol[j]==')') {
num2 = j;
break;
}
}
for(int index=num1+1;index<num2;index++) {
stack.push(charPol[index]);
}
StringBuilder polytemp = new StringBuilder(polynomial);
polynomial=polytemp.replace(num1, num2+1, "").toString();
}
if(polynomial.length()>0) {
charPol = polynomial.toCharArray();
for(int i=0;i<polynomial.length();i++) {
stack.push(charPol[i]);
}
}
}
System.out.print(value);
while(!(stack.isEmpty())) {
Character a = stack.pop();
System.out.println(" a is "+a);
value += Character.getNumericValue(a);
System.out.print("+"+a);
}
System.out.println();
return value;
}
public int getValue() {
// TODO Implement this method
return value;
}
public void setValue(int newValue) {
// TODO Implement this method
value = newValue;
}
}
最後，使用BabyCalculator的main（）方法。
package ds.test;
import java.util.Scanner;
public class Main {
public static void main(String[] args) {
BabyCalculator babyCalculator = new BabyCalculator();
Scanner sc = new Scanner(System.in);
while (sc.hasNext()) {
String command = sc.next();
if ("ADD".equals(command)) {
String equation = sc.next();
babyCalculator.murmurAdd(equation);
System.out.println("RESULT "+babyCalculator.getValue());
// TODO
} else if ("SHOW".equals(command)) {
System.out.println("VALUE "+babyCalculator.getValue());
// TODO
} else if ("CLEAR".equals(command)) {
babyCalculator.setValue(0);
System.out.println("VALUE CLEARED");
// TODO
} else if ("SET".equals(command)) {
int newValue = sc.nextInt();
babyCalculator.setValue(newValue);
System.out.println("VALUE SET TO "+babyCalculator.getValue());
// TODO
} else if ("EXIT".equals(command)) {
System.out.println("FINAL VALUE "+ babyCalculator.getValue());
return;
// TODO
}
}
sc.close();
}
}
編輯：當我試圖ADD（2345），其結果是
0+5+5+5+2
RESULT 17
這意味着5保持飛出只有等到它的時間爲2蹦出來。爲什麼這會繼續發生？我假設這是LinkedList類中的一個深層次的指向問題。
堆棧是你的界面？什麼是堆棧導入？我想嘗試你的代碼，但不能編譯... – Optional
哦，我認爲沒有必要的界面。我會導入它謝謝。 –
似乎你正在處理自定義接口。我認爲這是標準的JDK列表..我甚至無法編譯該類。 – Optional