使用深度优先实现查找简单路径并实现输出

#include<stdio.h>
#include <stdlib.h>
#include <string.h>//我这里的头以及尾巴与书上的不一样。
typedef struct ArcNode
{
    int from, to;
    struct ArcNode * fnext, *tonext;
    int w;
}ArcNode;
typedef struct VertexNode
{
    char info;
    ArcNode *ff, *ft;
}VertexNode;
typedef struct Graph
{
    int num_vertex;
    int num_arc;
    VertexNode *ver;
}Graph;
Graph *Create(int n)
{
    Graph * G = (Graph*)malloc(sizeof(Graph));
    G->num_vertex = n;
    G->num_arc = 0;
    G->ver = (VertexNode*)calloc(n+1, sizeof(VertexNode));
    for(int i = 1; i <= n; i++)
    {
        G->ver[i].ff = NULL;
        G->ver[i].ft = NULL;//在这里可以补加点的信息
    }
    return G;
}
void AddArc(Graph *G,int a, int b, int c)
{
    (G->num_arc)++;
    ArcNode *s = (ArcNode*)malloc(sizeof(ArcNode));
    s->from = a;
    s->to = b;
    s->fnext = G->ver[a].ff;
    G->ver[a].ff = s;
    s->tonext = G->ver[b].ft;
    G->ver[b].ft = s;
    s->w = c;
}
//深度优先查找最短路
void Print(int *pre,int x)
{
   int buf[1000];
   int cnt = 0;
   while(pre[x] != -1)
   {
       cnt++;
       buf[cnt] = x;
       x = pre[x];
   }
   for(int j = cnt; j >0; j--)
   {
       printf("%d ",buf[j]);
   }
}
int DFS(Graph *G,int *pre, int x, int y)
{
    for(ArcNode* j = G->ver[x].ff;j; j = j->fnext)
    {
        if(pre[j->to]==-1)
        {
            pre[j->to] = x;
            if(j->to == y)
            {
                Print(pre, y);
                return 1;
            }
            if(DFS(G, pre, j->to, y)) return 1;//很经典：这样可以在找到的时候快速的退出所有的递归调用。
        }
    }
    return 0;
}
void simple_track(Graph *G, int x, int y)
{
    int *pre = (int*)calloc(sizeof(G->num_vertex)+1, sizeof(int));
    for(int i = 1; i <= G->num_vertex; i++)
        pre[i] = -1;
    if(!DFS(G, pre, x, y))
    {
        printf("disabled!");
    }
    //free(pre);
}
int main()
{
    int n,m;
    scanf("%d",&n);
    Graph *G = Create(n);
    scanf("%d",&m);
    for(int i = 1; i <= m; i++)
    {
        int a, b;
        scanf("%d%d",&a, &b);
        AddArc(G,a,b,0);
    }
    int x, y;
    scanf("%d%d",&x, &y);
    simple_track(G, x, y);
    return 0;
}
/*
6 5
1 2
2 6
2 3
2 4
4 5
1 5
*/