用于查找链表长度的 Javascript 程序

编写一个函数来计算给定单链表中的节点数。

例如，对于链表 1->3->1->2->1，函数应该返回 5。

迭代解决方案：

1) Initialize count as 0 
2) Initialize a node pointer, current = head.
3) Do following while current is not NULL
     a) current = current -> next
     b) count++;
4) Return count 

以下是上述算法的迭代实现，用于查找给定单链表中的节点数。

Javascript

// Javascript program to count number
// of nodes in a linked list
 
// Linked list Node
class Node
{
    constructor(val)
    {
        this.data = val;
        this.next = null;
    }
}
 
// Head of list
var head;
 
// Inserts a new Node at front of the list.
function push(new_data)
{
    // 1 & 2: Allocate the Node & Put in
    // the data
    var new_node = new Node(new_data);
 
    // 3. Make next of new Node as head
    new_node.next = head;
 
    // 4. Move the head to point to new Node
    head = new_node;
}
 
// Returns count of nodes in linked list
function getCount()
{
    var temp = head;
    var count = 0;
    while (temp != null)
    {
        count++;
        temp = temp.next;
    }
    return count;
}
 
// Driver code
// Start with the empty list
push(1);
push(3);
push(1);
push(2);
push(1);
 
document.write("Count of nodes is " + getCount());
 
// This code contributed by Rajput-Ji

输出：

count of nodes is 5

递归解决方案：

int getCount(head)
1) If head is NULL, return 0.
2) Else return 1 + getCount(head->next) 

以下是上述算法的递归实现，用于查找给定单链表中的节点数。

Javascript

// Recursive javascript program to count
// number of nodes in a linked list
 
// Linked list Node
class Node
{
    constructor(val)
    {
        this.data = val;
        this.next = null;
    }
}
 
// Linked List class
// Head of list
var head;
 
// Inserts a new Node at front of the list.
function push( new_data)
{
    // 1 & 2: Allocate the Node &
    // Put in the data
    var new_node = new Node(new_data);
 
    // 3. Make next of new Node as head
    new_node.next = head;
 
    // 4. Move the head to point to new Node
    head = new_node;
}
 
Returns count of nodes in linked list
function getCountRec(node)
{
    // Base case
    if (node == null)
        return 0;
 
    // Count is this node plus rest
    // of the list
    return 1 + getCountRec(node.next);
}
 
// Wrapper over getCountRec()
function getCount()
{
    return getCountRec(head);
}
 
// Driver code
// Start with the empty list   
push(1);
push(3);
push(1);
push(2);
push(1);
 
document.write("Count of nodes is " + getCount());
 
// This code contributed by gauravrajput1

输出：

Count of nodes is 5

有关详细信息，请参阅有关查找链表长度（迭代和递归）的完整文章！