数据结构:单向链表系列3--删除节点

删除节点(3步操作)

删除步骤

1) 找到待删除节点的前驱

2) 修改前驱节点的指针域指向待删除节点的后继节点

3)释放待删除的节点的内存空间

//todo:没有c#的代码添加上去。修改结构，添加一个尾部节点地址的指针

c语言实现：

因为链表中的每个节点都是使用malloc()动态创建的,所以需要调用free()释放待删除节点占用的内存空间。

// A complete working C program to demonstrate deletion in singly 
// linked list 
#include <stdio.h> 
#include <stdlib.h> 

// A linked list node 
struct Node 
{ 
    int data; 
    struct Node *next; 
}; 

/* Given a reference (pointer to pointer) to the head of a list 
and an int, inserts a new node on the front of the list. */
void push(struct Node** head_ref, int new_data) 
{ 
    struct Node* new_node = (struct Node*) malloc(sizeof(struct Node)); 
    new_node->data = new_data; 
    new_node->next = (*head_ref); 
    (*head_ref) = new_node; 
} 

/* Given a reference (pointer to pointer) to the head of a list 
and a key, deletes the first occurrence of key in linked list */
void deleteNode(struct Node **head_ref, int key) 
{ 
    // Store head node 
    struct Node* temp = *head_ref, *prev; 

    // If head node itself holds the key to be deleted 
    if (temp != NULL && temp->data == key) 
    { 
        *head_ref = temp->next; // Changed head 
        free(temp);             // free old head 
        return; 
    } 

    // Search for the key to be deleted, keep track of the 
    // previous node as we need to change 'prev->next' 
    while (temp != NULL && temp->data != key) 
    { 
        prev = temp; 
        temp = temp->next; 
    } 

    // If key was not present in linked list 
    if (temp == NULL) return; 

    // Unlink the node from linked list 
    prev->next = temp->next; 

    free(temp); // Free memory 
} 

// This function prints contents of linked list starting from 
// the given node 
void printList(struct Node *node) 
{ 
    while (node != NULL) 
    { 
        printf(" %d ", node->data); 
        node = node->next; 
    } 
} 

/* Drier program to test above functions*/
int main() 
{ 
    /* Start with the empty list */
    struct Node* head = NULL; 

    push(&head, 7); 
    push(&head, 1); 
    push(&head, 3); 
    push(&head, 2); 

    puts("Created Linked List: "); 
    printList(head); 
    deleteNode(&head, 1); 
    puts("
Linked List after Deletion of 1: "); 
    printList(head); 
    return 0; 
}

因为涉及到遍历，时间复杂度O(n)

输出

Created Linked List: 
 2  3  1  7 
Linked List after Deletion of 1: 
 2  3  7 

java：

// A complete working Java program to demonstrate deletion in singly 
// linked list 
class LinkedList 
{ 
    Node head; // head of list 
  
    /* Linked list Node*/
    class Node 
    { 
        int data; 
        Node next; 
        Node(int d) 
        { 
            data = d; 
            next = null; 
        } 
    } 
  
    /* Given a key, deletes the first occurrence of key in linked list */
    void deleteNode(int key) 
    { 
        // Store head node 
        Node temp = head, prev = null; 
  
        // If head node itself holds the key to be deleted 
        if (temp != null && temp.data == key) 
        { 
            head = temp.next; // Changed head 
            return; 
        } 
  
        // Search for the key to be deleted, keep track of the 
        // previous node as we need to change temp.next 
        while (temp != null && temp.data != key) 
        { 
            prev = temp; 
            temp = temp.next; 
        }     
  
        // If key was not present in linked list 
        if (temp == null) return; 
  
        // Unlink the node from linked list 
        prev.next = temp.next; 
    } 
  
    /* Inserts a new Node at front of the list. */
    public void push(int new_data) 
    { 
        Node new_node = new Node(new_data); 
        new_node.next = head; 
        head = new_node; 
    } 
  
    /* This function prints contents of linked list starting from 
        the given node */
    public void printList() 
    { 
        Node tnode = head; 
        while (tnode != null) 
        { 
            System.out.print(tnode.data+" "); 
            tnode = tnode.next; 
        } 
    } 
  
    /* Drier program to test above functions. Ideally this function 
    should be in a separate user class. It is kept here to keep 
    code compact */
    public static void main(String[] args) 
    { 
        LinkedList llist = new LinkedList(); 
  
        llist.push(7); 
        llist.push(1); 
        llist.push(3); 
        llist.push(2); 
  
        System.out.println("
Created Linked list is:"); 
        llist.printList(); 
  
        llist.deleteNode(1); // Delete node at position 4 
  
        System.out.println("
Linked List after Deletion at position 4:"); 
        llist.printList(); 
    } 
} 

 文章来源：https://www.geeksforgeeks.org/linked-list-set-3-deleting-node/