在Java中使用數組實現Bag類/使用數組

Question

我在理解我的任務時遇到了一些困難，我只是想確保自己正確地做到了這一點，並希望在我的代碼中獲得另一雙眼睛。我的任務如下：

使用Array作爲基礎數據結構來實現一個Bag類，我已經完成了這個工作。在我們的UML圖中，我的導師顯示它是一個對象數組，我很困惑我應該如何用對象來做這件事，以及如何比較它們。我創建了一個Node類作爲對象，並將其附加到代碼的末尾。我主要的問題是我不知道如何處理聯合和包含，因此導致我質疑我的代碼的其餘部分。

public class Bag extends Node { 

    public Node array[]; 
    public Node header = new Node(null, null, null); 

    public int bagSize = 10000; // An Initial size of array for the Objects in 
    // the bag 

    public int MAX_SIZE = 1000000; // Max Size of elements in a undetermined 
    // size bag 

    static int count = 0; // Number of Elements currently in Bag 

    // Constructor for base Bag 
    // This bag has a maximum size 
    // bag that a bag can have 
    public Bag() { 
     array = new Node[MAX_SIZE]; 
     bagSize = MAX_SIZE; 
     array[count] = header; 

    } 

    // Constructor for bag of size 
    // which user can input 
    public Bag(int size) { 
     array = new Node[size]; 
     bagSize = size; 
     array[count] = header; 
    } 

    // Method which a user can add objects 
    // to the bag, the count will go up each 
    // time the method is called on the object. 
    public void add(Node newNode) { 
     int numOperations = 0; 
     Node n = new Node(); 
     numOperations++; 
     n = newNode; 
     numOperations++; 
     count++; 
     numOperations++; 
     array[count] = n; 
     numOperations++; 
     System.out.println("Operations = " + numOperations); 
    } 

    /** Remove a random Node from the bag **/ 
    public void removeRandom() { 

    } 

    /** Remove a specified Node from the bag **/ 
    public void remove(Node obj) { 
     int numOperations = 0; 
     int i; 
     numOperations++; 
     for (i = 0; i <= array.length - 1; i++) { 
      if (array[i] == obj) { 
       int pos = i; 
       numOperations++; 
       for (int j = i; j <= array.length - 1; j++) { 
        array[i] = array[i + 1]; 
        numOperations++; 
        if (i + 1 == array.length) 
         break; 
        numOperations++; 
       } 
       break; 
      } 
     } 

    } 

    /** Check is bag is empty **/ 
    public boolean isEmpty() { 
     System.out.println("Operations = 1"); 
     return (count == 0); 
    } 

    /** Check if bag contains the Node **/ 
    public boolean contains(String data) { 
     boolean contain = false; 
     if (!isEmpty()) { 
      for (int i = 0; i <= count; i++) { 
       if (data == array[i].data) { 
        return contain = true; 
       } else { 
        return contain = false; 
       } 
      } 
     } 
     return contain; 
    } 

    /** Return the size of bag **/ 
    public int size() { 
     return count; 
    } 

    /** Add all Nodes of bag a to the specified bag **/ 
    public static void addAll(Bag b, Bag a) { 
     int numOperations = 0; 
     if (b.bagSize >= a.size() + b.size()) { 
      numOperations++; 
      for (int i = 0; i <= a.size(); i++) { 
       b.add(b.array[i]); 
       numOperations++; 
      } 
     } 

    } 

    /** 
    * Join all elements of the two bags into a new bag but without any 
    * overlapping items. i.e No Duplicates 
    */ 
    public static Bag union(Bag a, Bag b) { 
     Bag bigger = new Bag(a.size() + b.size()); 
     if(!a.isEmpty() && !b.isEmpty() && a.equals(b)){ 
      for(int i=0;i<=bigger.bagSize;i++){ 
       if(a.contains(a.getData()) && b.contains(b.getData())){ 
        bigger.add(b.getNext());  
       }else{ 
        bigger.add(a.getNext()); 
        bigger.add(b.getNext()); 
       } 
      } 
     } 
     return b; 
    } 

    /** Determine if the bags equal each other in items **/ 
    public boolean equals(Bag a) { 
     if(bagSize == a.size()){ 

     } 
     return false; 
    } 
} 

---

public class Node { 
    String data; 
    Node prev,next; 

    public Node(Node next, Node prev, String data){ 
     this.next = next; 
     this.prev = prev; 
     this.data = data; 
    } 

    public Node(){ 

    } 

    public String getData() {return data;} 

    public Node getPrev() { return prev;} 

    public Node getNext() {return next;} 

    public void setData(String newName) {data = newName;} 

    public void setPrev(Node newPrev) { prev = newPrev; } 

    public void setNext(Node newNext) { next = newNext;} 

} 

Answer 1

你不需要Node類，你的包是由數組支持，創建一個鏈表是多餘的。

您的contains似乎是在正確的軌道上（但還沒有），它可能應該使用equals()而不是==。不過，您需要重新檢查如何處理contain標誌。

與工會有什麼問題？你能描述你是如何實現它的嗎（代碼不完全清楚）？