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("\nLinked 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("\nCreated Linked list is:"); llist.printList(); llist.deleteNode(1); // Delete node at position 4 System.out.println("\nLinked List after Deletion at position 4:"); llist.printList(); } }
文章来源：https://www.geeksforgeeks.org/linked-list-set-3-deleting-node/