给我一段拓补排序模板c++

以下是一个常见的拓扑排序模板示例，使用C语言实现：

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

#define MAXN 1000

struct Graph {
    int vn;
    int **e;
};

int vis[MAXN + 1];
int queue[MAXN + 1];
int head, tail;

void init_graph(struct Graph *g, int vn) {
    g->vn = vn;
    g->e = (int **) malloc(sizeof(int *) * (vn + 1));
    for (int i = 0; i <= vn; ++i) {
        g->e[i] = (int *) malloc(sizeof(int) * (vn + 1));
        for (int j = 0; j <= vn; ++j) {
            g->e[i][j] = 0;
        }
    }
}

void add_edge(struct Graph *g, int u, int v) {
    g->e[u][v] = 1;
}

int topological_sort(struct Graph *g, int *result) {
    int cnt = 0;
    head = tail = 0;
    for (int i = 1; i <= g->vn; ++i) {
        int indeg = 0;
        for (int j = 1; j <= g->vn; ++j) {
            if (g->e[j][i] > 0) indeg++;
        }
        if (indeg == 0) {
            queue[tail++] = i;
        }
    }
    while (head != tail) {
        int u = queue[head++];
        result[cnt++] = u;
        for (int v = 1; v <= g->vn; ++v) {
            if (g->e[u][v] > 0) {
                g->e[u][v] = 0;
                int indeg = 0;
                for (int j = 1; j <= g->vn; ++j) {
                    if (g->e[j][v] > 0) indeg++;
                }
                if (indeg == 0) {
                    queue[tail++] = v;
                }
            }
        }
    }
    return cnt == g->vn;
}

int main() {
    int n, m;
    scanf("%d%d", &n, &m);
    struct Graph *g = (struct Graph *) malloc(sizeof(struct Graph));
    init_graph(g, n);
    for (int i = 0; i < m; ++i) {
        int u, v;
        scanf("%d%d", &u, &v);
        add_edge(g, u, v);
    }
    int *result = (int *) malloc(sizeof(int) * (n + 1));
    if (topological_sort(g, result)) {
        for (int i = 0; i < n; ++i) {
            printf("%d ", result[i]);
        }
        printf("\n");
    } else {
        printf("There is a cycle in the graph.\n");
    }
    return 0;
}

这是一个简单的拓扑排序算法实现，用于解决有向无环图中的线性排序问题。其中，通过读入邻接矩阵来构建图，然后进行拓扑排序，最后输出排序结果或报告图中存在环路。