ME02

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

typedef struct node Node;
struct node{
    int SUCC;
    Node* NEXT;
};

void print(int n, int *COUNT, Node **LIST){
    Node *alpha;
    printf("num_vertex: %d\n", n);

    printf("------------------\n");
    for(int i=0; i<n; i++){
        printf("COUNT[%d]: %d\n", i+1, COUNT[i]);
        printf("\tLINK[%d]: ", i+1);
        alpha=LIST[i];
        while(alpha != NULL){
            printf(" %d", alpha->SUCC);
            alpha = alpha->NEXT;
        }
        printf("\n");
    }
}

int main()
{
    int n;
    scanf("%d",&n);
    int COUNT[n];
    Node* LIST[n];
    Node* alpha = NULL;

    for(int k = 0;k<=n;k++)
    {
        COUNT[k] = 0;
        LIST[k] =  NULL;
    }
    int m = n;
    int j,k;
    scanf("%d %d",&j,&k);
    while(j != 0 && k != 0)
    {
        alpha = (Node*) malloc(sizeof(Node));
        COUNT[k]++;
        alpha->SUCC = k;
        alpha->NEXT = LIST[j];
        LIST[j] = alpha;
        scanf("%d %d",&j,&k);
    }
    int front = 0,rear = 0;
    for(int k = 0;k<=n;k++)
    {
        if(COUNT[k]==0)
        {
            if(front==0)
            {
                front = k;
                rear = k;
            }
            else
            {
                COUNT[rear] = k;
                rear = k;
            }

        }
    }

    while(front != 0)
    {
        printf("%d ",front);
        m--;
        alpha = LIST[front];
        while(alpha != NULL)
        {
            k = alpha->SUCC;
            COUNT[k]--;
            if(COUNT[k] == 0)
            {
                COUNT[rear] = k;
                rear = k;
            }
            alpha = alpha->NEXT;
        }
        front = COUNT[front];
    }
    if(m > 0)
    {
        printf("Some objects comprise a loop");
    }


    return 0;
}