图的邻接列表表示法

writer：pprp

今天学的是邻接列表表示法

邻接列表表示法是用链表来记录各顶点的邻接顶点；

其节点结构为： 邻接顶点->下一邻接顶点->下一邻接顶点...

---

#include <iostream>

using namespace std;

const int N = 6;

struct node
{
    int vertex;
    node*next;
};

node head[N];

void create(int node1,int node2)//通过起点和终点的值创建一个邻接表
{
    node * point;
    node * New = new node();
    if(New!=NULL)
    {
        New->vertex = node2;
        New->next = NULL;
        point = &(head[node1]);
        while(point->next!=NULL)//注意这个地方应该是point->next而不是point,否则会越界
            point = point->next;
        point->next = New;
    }
}

void print()
{
    node*point;
    for(int i = 0; i < N; i++)
    {
        point = head[i].next;
        cout << "Head["<<i<<"]";
        while(point!=NULL)
        {
            cout <<"-> "<<point->vertex;
            point = point->next;
        }
        cout << endl;
    }
}

int main()
{
    int node1,node2;
    for(int i = 0; i < N;i++)
    {
          head[i].vertex = i;
          head[i].next = NULL;
    }
    while(1)
    {
          cout <<"please enter the start point" << endl;
          
          cin >> node1;
          if(node1 == -1)
            break;
          cout <<"please enter the end point" << endl;
          cin >> node2;
          
          if(node1 == node2)
            cout <<"自身循环"<<endl;
          else if(node1>=N||node2>=N)
            cout <<"超出范围"<<endl;
          else
            create(node1,node2);
    }
    
    cout << "邻接表为：" << endl;
    print();
    
    return 0;
}