數據結構:單向鏈表系列4--獲取鏈表長度(迭代法和遞歸法)

獲取鏈表長度(迭代法和遞歸法)

迭代法

1、設定一個計數器，初始值為0

2、初始化current到頭節點

3、如果current不為null進行以下循環

     a) current = current -> next
     b) count++;

4、返回計數器

c語言：

/* Counts no. of nodes in linked list */
int getCount(struct Node* head) 
{ 
    int count = 0;  // Initialize count 
    struct Node* current = head;  // Initialize current 
    while (current != NULL) { count++; current = current->next; } return count; } 

java：

 /* Returns count of nodes in linked list */
    public int getCount() 
    { 
        Node temp = head; int count = 0; while (temp != null) { count++; temp = temp.next; } return count; } 

c#:

 /* Returns count of nodes in linked list */
    public int getCount() 
    { 
        Node temp = head; int count = 0; while (temp != null) { count++; temp = temp.next; } return count; } 

 遞歸法

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

/* Counts the no. of occurrences of a node 
   (search_for) in a linked list (head)*/
int getCount(struct Node* head) 
{ 
    // Base case 
    if (head == NULL) return 0; // count is 1 + count of remaining list return 1 + getCount(head->next); }

java

  /* Returns count of nodes in linked list */
    public int getCountRec(Node node) 
    { 
        // Base case 
        if (node == null) return 0; // Count is this node plus rest of the list return 1 + getCountRec(node.next); }

c#

 /* Returns count of nodes in linked list */
    public int getCountRec(Node node)  
    {  
        // Base case  
        if (node == null) return 0; // Count is this node plus rest of the list return 1 + getCountRec(node.next); } 

 文章來源：https://www.geeksforgeeks.org/find-length-of-a-linked-list-iterative-and-recursive/