用c语言编写“链表数据存入无向图的信息文件和读取文件”

好的，我可以提供一些思路和代码示例。

首先，我们需要定义一个链表节点和图节点的结构体，它们的定义与前面提到的一样。

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

typedef struct GraphNode {
    int val;  // 节点值
    struct GraphNode *next;  // 指向下一个邻接节点的指针
} GraphNode;

然后我们可以定义一些函数来操作这个链表和图，比如创建节点、添加边等等。

// 创建一个新链表节点
ListNode *new_node(int val) {
    ListNode *node = (ListNode*)malloc(sizeof(ListNode));
    node->val = val;
    node->next = NULL;
    return node;
}

// 创建一个新图节点
GraphNode *new_graph_node(int val) {
    GraphNode *node = (GraphNode*)malloc(sizeof(GraphNode));
    node->val = val;
    node->next = NULL;
    return node;
}

// 将链表转换成图
GraphNode **list_to_graph(ListNode **list, int node_count) {
    GraphNode **graph = (GraphNode**)malloc(node_count * sizeof(GraphNode*));
    for (int i = 0; i < node_count; i++) {
        graph[i] = NULL;
    }
    ListNode *node = *list;
    while (node) {
        ListNode *cur = node;
        node = node->next;
        free(cur);
        GraphNode *graph_node = new_graph_node(cur->val);
        graph_node->next = graph[cur->val];
        graph[cur->val] = graph_node;
    }
    *list = NULL;
    return graph;
}

// 将图转换成链表
ListNode **graph_to_list(GraphNode **graph, int node_count) {
    ListNode **list = (ListNode**)malloc(sizeof(ListNode*));
    *list = NULL;
    for (int i = 0; i < node_count; i++) {
        GraphNode *node = graph[i];
        while (node) {
            ListNode *list_node = new_node(node->val);
            list_node->next = *list;
            *list = list_node;
            node = node->next;
        }
    }
    return list;
}

// 从文件中读取图的信息
GraphNode **read_graph(char *filename, int *node_count, int *edge_count) {
    FILE *fp = fopen(filename, "r");
    if (!fp) {
        printf("Failed to open file %s\n", filename);
        return NULL;
    }
    fscanf(fp, "%d %d", node_count, edge_count);
    GraphNode **graph = (GraphNode**)malloc(*node_count * sizeof(GraphNode*));
    for (int i = 0; i < *node_count; i++) {
        graph[i] = NULL;
    }
    for (int i = 0; i < *edge_count; i++) {
        int u, v;
        fscanf(fp, "%d %d", &u, &v);
        GraphNode *node = new_graph_node(v);
        node->next = graph[u];
        graph[u] = node;
        node = new_graph_node(u);
        node->next = graph[v];
        graph[v] = node;
    }
    fclose(fp);
    return graph;
}

// 保存图的信息到文件
void save_graph(GraphNode **graph, int node_count, int edge_count, char *filename) {
    FILE *fp = fopen(filename, "w");
    if (!fp) {
        printf("Failed to open file %s\n", filename);
        return;
    }
    fprintf(fp, "%d %d\n", node_count, edge_count);
    for (int i = 0; i < node_count; i++) {
        GraphNode *node = graph[i];
        while (node) {
            if (node->val > i) {
                fprintf(fp, "%d %d\n", i, node->val);
            }
            node = node->next;
        }
    }
    fclose(fp);
}

最后，我们可以在主函数中调用这些函数来创建链表、将链表转换成图、保存到文件、从文件中读取图的信息并将图转换成链表。

int main() {
    // 创建一个新链表
    ListNode *list = NULL;
    for (int i = 0; i < 5; i++) {
        ListNode *node = new_node(i);
        node->next = list;
        list = node;
    }
    // 将链表转换成图
    GraphNode **graph = list_to_graph(&list, 5);
    // 保存到文件
    save_graph(graph, 5, 4, "graph.txt");
    // 从文件中读取图的信息
    int node_count, edge_count;
    GraphNode **new_graph = read_graph("graph.txt", &node_count, &edge_count);
    // 将图转换成链表
    ListNode **new_list = graph_to_list(new_graph, node_count);
    // 打印链表的值
    ListNode *node = *new_list;
    while (node) {
        printf("%d ", node->val);
        node = node->next;
    }
    printf("\n");
    return 0;
}

这样，我们就可以用 C 语言编写链表数据存入无向图的信息文件和读取文件了。