Algorithms_DFS, Topology Sort

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

struct node{
    int nb[10];
    int nbLen;
    int color;
    int from;
    int touch;
    int finish;
};

struct node N[10];

struct tuple{
    int ind;
    int fnsh;
};

//struct node T;
//T.nbLen;
//scanf("%d", &T.nb[2]);
//scanf("%d", N[2].nb[8]);
int nl, nbl;
int time;

int arr[10];
int len = 10;
int top = -1;
int isFull();
int isEmpty();
int push(int n);
int pop();

// void printStack();

int isFull(){
    if(top == len-1)
        return 1;
    else
        return 0;
}

int isEmpty(){
    if(top <= -1)
        return 1;
    else
        return 0;
}

int push(int n){
    if(isFull() != 1){
        top++;
        arr[top] = n;
        return 1;
    }else{
        printf("full");
        return 0;
    }
}

int pop(){
    if(isEmpty() != 1){
        top--;
        return arr[top+1];
    }else{
        printf("is Empty");
        return -1;
    }
}

//void printStack(){
//  int i;
//  for(i = 0; i <= top; i++)
//      printf("%d ", arr[i]);
//
//  printf("\n");
//}

void printNB(int n){
    int i;
    for(i = 0; i < N[n].nbLen ; i++)
        printf("%d ", N[n].nb[i]);

    printf("\n");
}

int initialize(){
    int i;
    for(i = 0; i < nl; i++){
        N[i].color = 100;
        N[i].from = -1;
        N[i].touch = 0;
        N[i].finish = 0;
    }

    time = 1;
}

void DFS(int m){
    push(m);
    N[m].color = 200;
    N[m].touch = time;
    time++;
    int j;
    for(j = 0; j < N[m].nbLen; j++){
        if(N[ N[m].nb[j] ].color == 100)
            DFS(N[m].nb[j]);
    }

    pop();
    N[m].color = 300;
    N[m].finish = time;
    time++;
}

int compare(const void *a, const void *b){
    struct tuple* A = (struct tuple*)a;
    struct tuple* B = (struct tuple*)b;
    if (A[0].fnsh < B[0].fnsh) return 1;
    else if (A[0].fnsh > B[0].fnsh) return -1;
    else return 0;
}

void print(){
    struct tuple M[10];
    int i;
    for(i = 0; i < nl; i++){
        M[i].ind = i;
        M[i].fnsh = N[i].finish;
    }

    qsort(M, nl, sizeof(struct tuple), compare);
    for(i = 0; i < nl; i++)
        printf("%d ", M[i].ind);

}

int main(){
    int i;
//  for(i=0;i<7;i++) push(i*10);
//  printStack();
//  for(i=0;i<4;i++) printf("%d ",pop());
//  printf("\n");
//  for(i=0;i<8;i++) push(i*100);
//  printStack();
    int index, x, y;
    scanf("%d %d", &nl, &nbl);
    for(i = 0; i < nl; i++)
        N[i].nbLen = 0;

    for(i = 0; i < nbl; i++){
        scanf("%d", &x);
        scanf("%d", &y);
        index = N[x].nbLen;
        N[x].nb[ index ] = y;
        N[x].nbLen++;
    }
//  for(i = 0; i < nl; i++) printNB(i);
    initialize();
    int j;
    for(j = 0; j < nl; j++){
        if(N[j].color == 100)
            DFS(j);
    }
//  for(j = 0; j < nl; j++) printf("%d, %d\n", N[j].touch, N[j].finish);
    print();
    return 0;
}