c语言编写完整代码 假设带权有向图采用邻接表存储，顶点i,j已存在，设计一个算法删除一条给定的边<i,j>

以下是使用邻接表存储的带权有向图删除一条给定边的C语言代码：

#include <stdio.h>
#include <stdlib.h>

#define MAX_VERTICES 100

// 结点结构体
typedef struct node {
    int vertex;  // 顶点
    int weight;  // 权重
    struct node* next;  // 下一个结点
} Node;

// 邻接表结构体
typedef struct graph {
    Node* vertices[MAX_VERTICES];  // 顶点数组
    int num_vertices;  // 顶点数
} Graph;

// 初始化邻接表
void initGraph(Graph* graph) {
    graph->num_vertices = 0;
    for (int i = 0; i < MAX_VERTICES; i++) {
        graph->vertices[i] = NULL;
    }
}

// 添加边
void addEdge(Graph* graph, int from_vertex, int to_vertex, int weight) {
    Node* new_node = (Node*)malloc(sizeof(Node));
    new_node->vertex = to_vertex;
    new_node->weight = weight;
    new_node->next = graph->vertices[from_vertex];
    graph->vertices[from_vertex] = new_node;
}

// 删除边
void deleteEdge(Graph* graph, int from_vertex, int to_vertex) {
    Node* curr_node = graph->vertices[from_vertex];
    Node* prev_node = NULL;
    while (curr_node != NULL) {
        if (curr_node->vertex == to_vertex) {  // 找到目标结点
            if (prev_node == NULL) {  // 目标结点是第一个结点
                graph->vertices[from_vertex] = curr_node->next;
            } else {  // 目标结点不是第一个结点
                prev_node->next = curr_node->next;
            }
            free(curr_node);
            return;
        }
        prev_node = curr_node;
        curr_node = curr_node->next;
    }
}

// 打印邻接表
void printGraph(Graph* graph) {
    for (int i = 0; i < graph->num_vertices; i++) {
        printf("%d:", i);
        Node* curr_node = graph->vertices[i];
        while (curr_node != NULL) {
            printf(" %d(%d)", curr_node->vertex, curr_node->weight);
            curr_node = curr_node->next;
        }
        printf("\n");
    }
}

int main() {
    Graph graph;
    initGraph(&graph);

    // 添加边
    addEdge(&graph, 0, 1, 2);
    addEdge(&graph, 0, 2, 3);
    addEdge(&graph, 1, 2, 4);
    addEdge(&graph, 2, 3, 5);
    addEdge(&graph, 3, 1, 6);

    printf("Before deleting edge:\n");
    printGraph(&graph);

    // 删除边
    deleteEdge(&graph, 0, 1);

    printf("After deleting edge:\n");
    printGraph(&graph);

    return 0;
}

假设要删除的边是<i,j>，则可以在邻接表中遍历顶点i的链表，找到目标结点j，然后将目标结点从链表中删除即可。如果顶点i的链表中没有目标结点j，则说明要删除的边不存在。上述代码中的`deleteEdge()`函数就是删除边的具体实现。