[算法] aov图拓扑算法

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

using namespace std;

#define MAX 100

struct Node{
    int value;
    struct Node* nextNode;
};

struct LGraph{
    struct Node vertexs[MAX];
    int ids[MAX];
    int vexnum;
    int edgenum;
} lg;

void create_lg(){
    int u,v;
    int i;
    struct Node *pi;
    for(i = 0; i < lg.edgenum; i++){
        scanf("%d%d", &u, &v);
        u --; v --;
        pi = (struct Node*)malloc(sizeof(struct Node));
        pi->value = v;
        pi->nextNode = lg.vertexs[u].nextNode;
        lg.vertexs[u].nextNode = pi;
        lg.ids[v] ++;
    }
}

void sort() {
    int i;
    int index = 0;
    int count[MAX];
    memset(count, 0, sizeof(count));
    queue<int> Q;
    for(i = 0; i < lg.vexnum; i++){
        if(0 == lg.ids[i]){
            Q.push(i);
        }
    }
    while(!Q.empty()){
        int node;
        struct Node * pi;
        struct Node * tmp;
        node = Q.front();
        count[index++] = node;
        Q.pop();
        pi = lg.vertexs[node].nextNode;
        while(pi){
            int v = pi->value;
            lg.ids[v] --;
            if(lg.ids[v] == 0) {
                Q.push(v);
            }
            tmp = pi;
            pi = pi->nextNode;
            free(tmp);
            lg.edgenum --;
        }
    }
    if(index == lg.vexnum){
        for(i = 0; i < index; i++){
            if(i == 0){
                printf("%d", count[i] + 1);
            }
            else{
                printf(" %d", count[i] + 1);
            }
        }
        printf("\n");
    }
    else{
        printf("Network has a cycle!\n");
    } 

}

void delete_lg(){
    int i;
    struct Node * pi;
    for( i = 0; i < lg.vexnum; i++){
        pi = lg.vertexs[i].nextNode;
        while(pi) {
            pi = pi->nextNode;
            free(pi);
        }
    }
}

void init_lg(){
    lg.vexnum = 0;
    lg.edgenum = 0;
    memset(lg.vertexs, 0, sizeof(lg.vertexs));
    memset(lg.ids, 0, sizeof(lg.ids));
    delete_lg();
}

int N, M;

int main() {
    int i; 

    while(1) {
        scanf("%d%d", &N, &M);
        if( 0 == N && 0 == M) {
            break;
        }
        init_lg();
        lg.vexnum = N;
        lg.edgenum = M;
        create_lg();
        sort();
    }
    init_lg();
    return 0;
}

假设输入文件中有向图的格式为：首先是顶点个数 n 和边数 m；然后是每条边，每条边的数
据占一行，格式为 u v，表示从顶点 u 到顶点 v 的一条有向边，顶点序号从 1 开始计起。输入文件
最后一行为 0 0，表示输入数据结束。
样例输入：

6 8
1 2
1 4
2 6
3 2
3 6
5 1
5 2
5 6
6 8
1 3
1 2
2 5
3 4
4 2
4 6
5 4
5 6
0 0

样例输出：

3 5 1 4 2 6
Network has a cycle!