Java中的通用链接列表联盟

Question

在这个程序中，我做了一个通用的链表。插入和显示功能工作正常，但联合功能不工作。我实际上不确定我写的功能是正确的还是不是这样，我如何执行两个给定列表的联合。

import java.util.*; 

class Node<T> { 
    T data; 
    Node<T> next; 

    Node(T d) { 
     data = d; 
    } 

    void display() { 
     System.out.println(data + " "); 
    } 
} 

class List<T> { 
    Node<T> first; 

    List() { 
     first = null; 
    } 

    void insert(T data) { 
     Node<T> newnode = new Node<T>(data); 
     if (first == null) 
      first = newnode; 
     else { 
      Node<T> temp = first; 
      while (temp.next != null) 
       temp = temp.next; 
      temp.next = newnode; 
     } 
    } 

    void display() { 
     if (first == null) 
      System.out.println("EmpTY"); 
     else { 
      Node<T> temp = first; 
      while (temp != null) { 
       temp.display(); 
       temp = temp.next; 
      } 
     } 
    } 

    public void union(Node<Double> head1, Node<Double> head2) { 
     Node<T> t = head1; 
     Node<T> t1 = head2; 
     while (t != null && t1 != null) { 
      if (t.data > t1.data) { 
       System.out.println(t.data + "\n"); 
       t = t.next; 
      } else if (t.data < t1.data) { 
       System.out.println(t1.data + "\n"); 
       t1 = t1.next; 
      } else { 
       System.out.println(t.data + "\n"); 
       System.out.println(t.data + "\n"); 
       t = t.next; 
       t1 = t1.next; 
      } 
     } 
    } 
} 

class DEMO { 
    public static void main(String args[]) { 
     List<Double> l1 = new List<Double>(); 
     for (double i = 0; i < 5; i++) { 
      l1.insert(i); 
     } 
     l1.display(); 
     List<Double> l2 = new List<Double>(); 
     List<Double> l3 = new List<Double>(); 
     for (double j = 0; j < 5; j++) { 
      l2.insert(j); 
     } 
     l3.union(l1, l2); 
    } 
} 

Answer 1

你可以做这样的事情：

/* Function to get Union of 2 Linked Lists */ 
void doUnion(Node head1, Node head2) { 
    Node t1 = head1, t2 = head2; 
    //insert all elements of list1 in the result 
    while (t1 != null) { 
     push(t1.data); 
     t1 = t1.next; 
    } 
    // insert those elements of list2 that are not present 
    while (t2 != null) { 
     if (!isPresent(head, t2.data)) { 
      push(t2.data); 
     } 
     t2 = t2.next; 
    } 
} 

/* Inserts a node at start of linked list */ 
void push(int new_data) { 
    /* 1. Allocate the Node & Put in the data*/ 
    Node new_node = new Node(new_data); 
    /* 2. Make next of new Node as head */ 
    new_node.next = head; 
    /* 3. Move the head to point to new Node */ 
    head = new_node; 
} 

/* A utilty function that returns true if data is present in linked list else return false */ 
boolean isPresent(Node head, int data) { 
    Node t = head; 
    while (t != null) { 
     if (t.data == data) { 
      return true; 
     } 
     t = t.next; 
    } 
    return false; 
}