计算图的聚类系数C语言代码

计算图的聚类系数可以用 C 语言实现。下面是一个简单的实现示例：

#include <stdio.h>

#define MAX_NODES 100

int graph[MAX_NODES][MAX_NODES];
int node_degrees[MAX_NODES];

int get_triangle_count(int node) {
    int i, j, k, count = 0;
    for (i = 0; i < node_degrees[node]; i++) {
        for (j = i+1; j < node_degrees[node]; j++) {
            for (k = j+1; k < node_degrees[node]; k++) {
                if (graph[node_degrees[node][i]][node_degrees[node][j]] &&
                    graph[node_degrees[node][i]][node_degrees[node][k]] &&
                    graph[node_degrees[node][j]][node_degrees[node][k]]) {
                    count++;
                }
            }
        }
    }
    return count;
}

double get_clustering_coefficient(int node) {
    int degree = node_degrees[node];
    if (degree < 2) {
        return 0;
    }
    int triangle_count = get_triangle_count(node);
    if (triangle_count == 0) {
        return 0;
    }
    int max_triangles = degree * (degree - 1) / 2;
    return ((double)triangle_count) / max_triangles;
}

int main() {
    int n, m, i, j, k;
    scanf("%d %d", &n, &m);
    for (i = 0; i < m; i++) {
        scanf("%d %d", &j, &k);
        graph[j][k] = graph[k][j] = 1;
        node_degrees[j]++;
        node_degrees[k]++;
    }
    double total_coefficient = 0;
    for (i = 0; i < n; i++) {
        double coefficient = get_clustering_coefficient(i);
        printf("Clustering coefficient of node %d: %lf\n", i, coefficient);
        total_coefficient += coefficient;
    }
    double average_coefficient = total_coefficient / n;
    printf("Average clustering coefficient: %lf\n", average_coefficient);
    return 0;
}

这个程序的输入为两个整数 n 和 m，表示节点数和边数。接下来的 m 行每行包含两个整数 j 和 k，表示 j 和 k 之间有一条边。程序使用邻接矩阵存储图，并计算每个节点的聚类系数。最后输出每个节点的聚类系数以及整个图的平均聚类系数。