多级链表

多级链表
多级链表是一种二维数据结构，由多个链表组成，多级链表中的每个节点都有一个 next 和 child 指针。所有元素都使用指针链接。

多级链表

表示：
多级链表由指向链表第一个节点的指针表示。与链表类似，第一个节点称为头。如果多级链表为空，则 head 的值为 NULL。列表中的每个节点至少包含三个部分：
1.数据。
2.指向下一个节点的指针。
3.指向子节点的指针。

多级链表的每个节点表示为：

class Node
{
        public:
                 int data;
                 Node *next;
                 Node *child;
 };

下面是多级链表的实现

C++

// C++ program to implement
// a multilevel linked list
 
#include 
using namespace std;
 
// Representation of node
class Node {
public:
    int data;
    Node* next;
    Node* child;
};
 
// A function to create a linked list
// with n(size) nodes returns head pointer
Node* createList(int* arr, int n)
{
    Node* head = NULL;
    Node* tmp;
 
    // Traversing the passed array
    for (int i = 0; i < n; i++) {
        // Creating a node if the list
        // is empty
        if (head == NULL) {
            tmp = head = new Node();
        }
        else {
            tmp->next = new Node();
            tmp = tmp->next;
        }
        // Created a node with data and
        // setting child and next pointer
        // as NULL.
        tmp->data = arr[i];
        tmp->next = tmp->child = NULL;
    }
    return head;
}
 
// To print the linked list
void printMultiLevelList(Node* head)
{
    // While head is not null
    while (head) {
        if (head->child) {
            printMultiLevelList(head->child);
        }
        cout << head->data << " ";
        head = head->next;
    }
}
 
// Driver code
int main()
{
    // Initializing the data in arrays(row wise)
    int arr1[3] = { 1, 2, 3 };
    int arr2[2] = { 5, 6 };
    int arr3[1] = { 4 };
    int arr4[3] = { 7, 8, 9 };
 
    // creating Four linked lists
    // Passing array and size of array
    // as parameters
    Node* head1 = createList(arr1, 3);
    Node* head2 = createList(arr2, 2);
    Node* head3 = createList(arr3, 1);
    Node* head4 = createList(arr4, 3);
 
    // Initializing children and next pointers
    // as shown in given diagram
    head1->child = head2;
    head1->next->next->child = head3;
    head2->next->child = head4;
 
    // Creating a null pointer.
    Node* head = NULL;
    head = head1;
 
    // Function Call to print
    printMultiLevelList(head);
 
    return 0;
}

Java

/*package whatever //do not write package name here */
import java.io.*;
 
class GFG {
   public static class Node {
      int data;
        Node next;
        Node child;
    };
 
    // A function to create a linked list
    // with n(size) nodes returns head pointer
    public static Node createList(int arr[], int n)
    {
        Node head = null;
        Node tmp = null;
 
        // Traversing the passed array
        for (int i = 0; i < n; i++)
        {
 
            // Creating a node if the list
            // is empty
            if (head == null) {
                tmp = head = new Node();
            }
            else {
                tmp.next = new Node();
                tmp = tmp.next;
            }
 
            // Created a node with data and
            // setting child and next pointer
            // as NULL.
            tmp.data = arr[i];
            tmp.next = tmp.child = null;
        }
        return head;
    }
 
    // To print the linked list
    public static void printMultiLevelList(Node head)
    {
 
        // While head is not null
        while (head != null) {
            if (head.child != null) {
                printMultiLevelList(head.child);
            }
            System.out.print(head.data + " ");
            head = head.next;
        }
    }
 
    // Driver code
    public static void main(String[] args)
    {
        int arr1[] = { 1, 2, 3 };
        int arr2[] = { 5, 6 };
        int arr3[] = { 4 };
        int arr4[] = { 7, 8, 9 };
 
        // creating Four linked lists
        // Passing array and size of array
        // as parameters
        Node head1 = createList(arr1, 3);
        Node head2 = createList(arr2, 2);
        Node head3 = createList(arr3, 1);
        Node head4 = createList(arr4, 3);
 
        // Initializing children and next pointers
        // as shown in given diagram
        head1.child = head2;
        head1.next.next.child = head3;
        head2.next.child = head4;
 
        // Creating a null pointer.
        Node head = null;
        head = head1;
 
        // Function Call to print
        printMultiLevelList(head);
    }
}
 
// This code is contributed by maddler.

Python3

'''package whatever #do not write package name here '''
class Node:
    def __init__(self):
        self.data = 0;
        self.next = None;
        self.child = None;
 
# A function to create a linked list
# with n(size) Nodes returns head pointer
def createList(arr, n):
    head = None;
    tmp = None;
 
    # Traversing the passed array
    for i in range(n):
 
        # Creating a Node if the list
        # is empty
        if (head == None):
            tmp = head = Node();
        else:
            tmp.next = Node();
            tmp = tmp.next;
         
        # Created a Node with data and
        # setting child and next pointer
        # as NULL.
        tmp.data = arr[i];
        tmp.next = tmp.child = None;
     
    return head;
 
# To print linked list
def printMultiLevelList(head):
 
    # While head is not None
    while (head != None):
        if (head.child != None):
            printMultiLevelList(head.child);
         
        print(head.data, end=" ");
        head = head.next;
     
# Driver code
if __name__ == '__main__':
    arr1 = [ 1, 2, 3 ];
    arr2 = [ 5, 6] ;
    arr3 = [ 4 ];
    arr4 = [ 7, 8, 9] ;
 
    # creating Four linked lists
    # Passing array and size of array
    # as parameters
    head1 = createList(arr1, 3);
    head2 = createList(arr2, 2);
    head3 = createList(arr3, 1);
    head4 = createList(arr4, 3);
 
    # Initializing children and next pointers
    # as shown in given diagram
    head1.child = head2;
    head1.next.next.child = head3;
    head2.next.child = head4;
 
    # Creating a None pointer.
    head = None;
    head = head1;
 
    # Function Call to print
    printMultiLevelList(head);
 
# This code is contributed by umadevi9616

C#

/*package whatever //do not write package name here */
using System;
 
public class GFG {
   public class Node {
          public int data;
        public Node next;
        public Node child;
    };
 
    // A function to create a linked list
    // with n(size) nodes returns head pointer
    public static Node createList(int []arr, int n)
    {
        Node head = null;
        Node tmp = null;
 
        // Traversing the passed array
        for (int i = 0; i < n; i++)
        {
           
            // Creating a node if the list
            // is empty
            if (head == null) {
                tmp = head = new Node();
            }
            else {
                tmp.next = new Node();
                tmp = tmp.next;
            }
           
            // Created a node with data and
            // setting child and next pointer
            // as NULL.
            tmp.data = arr[i];
            tmp.next = tmp.child = null;
        }
        return head;
    }
 
    // To print the linked list
    public static void printMultiLevelList(Node head)
    {
       
        // While head is not null
        while (head != null) {
            if (head.child != null) {
                printMultiLevelList(head.child);
            }
            Console.Write(head.data + " ");
            head = head.next;
        }
    }
 
    // Driver code
    public static void Main(String[] args)
    {
        int []arr1 = { 1, 2, 3 };
        int []arr2 = { 5, 6 };
        int []arr3 = { 4 };
        int []arr4 = { 7, 8, 9 };
 
        // creating Four linked lists
        // Passing array and size of array
        // as parameters
        Node head1 = createList(arr1, 3);
        Node head2 = createList(arr2, 2);
        Node head3 = createList(arr3, 1);
        Node head4 = createList(arr4, 3);
 
        // Initializing children and next pointers
        // as shown in given diagram
        head1.child = head2;
        head1.next.next.child = head3;
        head2.next.child = head4;
 
        // Creating a null pointer.
        Node head = null;
        head = head1;
 
        // Function Call to print
        printMultiLevelList(head);
    }
}
 
// This code is contributed by shikhasingrajput

Javascript

/*package whatever //do not write package name here */
    class Node {
        constructor(){
      this.data = 0;
        this.next = null;
        this.child = null;
        }
    }
 
    // A function to create a linked list
    // with n(size) nodes returns head pointer
    function createList(arr , n)
    {
        var head = null;
        var tmp = null;
 
        // Traversing the passed array
        for (var i = 0; i < n; i++)
        {
           
            // Creating a node if the list
            // is empty
            if (head == null) {
                tmp = head = new Node();
            }
            else {
                tmp.next = new Node();
                tmp = tmp.next;
            }
           
            // Created a node with data and
            // setting child and next pointer
            // as NULL.
            tmp.data = arr[i];
            tmp.next = tmp.child = null;
        }
        return head;
    }
 
    // To print the linked list
    function printMultiLevelList(head)
    {
       
        // While head is not null
        while (head != null) {
            if (head.child != null) {
                printMultiLevelList(head.child);
            }
            document.write(head.data + " ");
            head = head.next;
        }
    }
 
    // Driver code
 
        var arr1 = [ 1, 2, 3 ];
        var arr2 = [ 5, 6 ];
        var arr3 = [ 4 ];
        var arr4 = [ 7, 8, 9 ];
 
        // creating Four linked lists
        // Passing array and size of array
        // as parameters
        var head1 = createList(arr1, 3);
        var head2 = createList(arr2, 2);
        var head3 = createList(arr3, 1);
        var head4 = createList(arr4, 3);
 
        // Initializing children and next pointers
        // as shown in given diagram
        head1.child = head2;
        head1.next.next.child = head3;
        head2.next.child = head4;
 
        // Creating a null pointer.
        var head = null;
        head = head1;
 
        // Function Call to print
        printMultiLevelList(head);
 
// This code is contributed by Rajput-Ji

输出

5 7 8 9 6 1 2 4 3