C语言链表操作

链表是一种常见的数据结构，它可以用来实现各种算法和数据结构。C语言中，链表可以通过结构体和指针来实现。下面是链表的基本操作：

1. 定义链表节点结构体

struct ListNode {
    int val;
    struct ListNode *next;
};

2. 创建链表节点

struct ListNode* createNode(int val) {
    struct ListNode* node = (struct ListNode*)malloc(sizeof(struct ListNode));
    node->val = val;
    node->next = NULL;
    return node;
}

3. 插入节点到链表头部

void insertAtHead(struct ListNode** head, int val) {
    struct ListNode* node = createNode(val);
    node->next = *head;
    *head = node;
}

4. 插入节点到链表尾部

void insertAtTail(struct ListNode** head, int val) {
    struct ListNode* node = createNode(val);
    if (*head == NULL) {
        *head = node;
        return;
    }
    struct ListNode* tail = *head;
    while (tail->next != NULL) {
        tail = tail->next;
    }
    tail->next = node;
}

5. 删除节点

void deleteNode(struct ListNode** head, int val) {
    struct ListNode* cur = *head;
    struct ListNode* prev = NULL;
    while (cur != NULL && cur->val != val) {
        prev = cur;
        cur = cur->next;
    }
    if (cur == NULL) {
        return;
    }
    if (prev == NULL) {
        *head = cur->next;
    } else {
        prev->next = cur->next;
    }
    free(cur);
}

6. 查找节点

struct ListNode* searchNode(struct ListNode* head, int val) {
    struct ListNode* cur = head;
    while (cur != NULL && cur->val != val) {
        cur = cur->next;
    }
    return cur;
}

7. 遍历链表

void printList(struct ListNode* head) {
    struct ListNode* cur = head;
    while (cur != NULL) {
        printf("%d ", cur->val);
        cur = cur->next;
    }
    printf("\n");
}

这些是链表的基本操作，可以根据需要进行扩展。