单链表的基本操作C语言版本

单链表是一种常见的数据结构，以下是单链表的基本操作C语言版本：

1. 定义单链表节点结构体

typedef struct ListNode {
    int val; // 节点的值
    struct ListNode *next; // 指向下一个节点的指针
} ListNode;

2. 创建单链表

ListNode* createList(int arr[], int n) {
    ListNode *head = NULL, *tail = NULL;
    for (int i = 0; i < n; i++) {
        ListNode *node = (ListNode*)malloc(sizeof(ListNode));
        node->val = arr[i];
        node->next = NULL;
        if (head == NULL) {
            head = tail = node;
        } else {
            tail->next = node;
            tail = node;
        }
    }
    return head;
}

3. 遍历单链表

void traverseList(ListNode *head) {
    ListNode *p = head;
    while (p != NULL) {
        printf("%d ", p->val);
        p = p->next;
    }
}

4. 插入节点

void insertNode(ListNode **head, int val, int pos) {
    ListNode *node = (ListNode*)malloc(sizeof(ListNode));
    node->val = val;
    node->next = NULL;
    if (*head == NULL) {
        *head = node;
        return;
    }
    if (pos == 0) {
        node->next = *head;
        *head = node;
        return;    }
    ListNode *p = *head;
    for (int i = 0; i < pos - 1 && p != NULL; i++) {
        p = p->next;
    }
    if (p == NULL) {
        return;
    }
    node->next = p->next;
    p->next = node;
}

5. 删除节点

void deleteNode(ListNode **head, int pos) {
    if (*head == NULL) {
        return;
    }
    if (pos == 0) {
        ListNode *p = *head;
        *head = (*head)->next;
        free(p);
        return;
    }
    ListNode *p = *head;
    for (int i = 0; i < pos - 1 && p != NULL; i++) {
        p = p->next;
    }
    if (p == NULL || p->next == NULL) {
        return;
    }
    ListNode *q = p->next;
    p->next = q->next;
    free(q);
}