数据结构之图的遍历BFS 邻接表+链栈

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BFS需要用到队列，习惯了链栈，感觉链栈比较好写，循环队列以后再补吧。图的存储习惯用邻接表，虽然麻烦些，但是很好遍历。

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#include <bits/stdc++.h>   //BFS 链栈 + 邻接表存图
using namespace std;
typedef struct Arcnode{
    int vertex,data;                //这条边的终点 以及权值
    struct Arcnode *nextArc;              //与这条边同起点的下一条边
}Arcnode;
typedef struct vernode{
    int data;                   //顶点数据
     Arcnode *nextArc;            // 以该点为起点的边
}vernode;
typedef struct {
    vernode vertex[1001];
    int vernum,arcnum;
}Graph;
typedef struct Qnode{
    int data;
    struct Qnode *next;
}Qnode,*Qptr;
typedef struct {
    Qptr front;
    Qptr rear;
}Linkqueue;
int vis[1001];
int locate(Graph G, int x)
{
    for(int i = 1 ; i <= G.vernum; ++i)
    {
        if(G.vertex[i].data == x)
        {
            return i;
        }
    }
}
void create(Graph &G)
{
    int a,b,w;
    cin >> G.vernum >> G.arcnum;
    for(int i = 1; i <= G.vernum ; ++i)
    {
        cin >> G.vertex[i].data;
        G.vertex[i].nextArc = NULL;
    }
    for(int i = 1; i <= G.arcnum; ++i)
    {
        cin >> a >> b >> w;
        int A = locate(G,a);
        int B = locate(G,b);
        Arcnode *p,*p1;
        p = new Arcnode;             //！！！这一步总是忘记
        p -> vertex = B;
        p -> nextArc = G.vertex[A].nextArc;
        p -> data = w;
        G.vertex[A].nextArc = p;
        p = new Arcnode;
        p -> vertex = A;
        p -> nextArc = G.vertex[B].nextArc;
        p -> data = w;
        G.vertex[B].nextArc = p;
    }
}
void init(Linkqueue &Q)
{
    Q.front = new Qnode;
    Q.front -> next = NULL;
    Q.rear = Q.front;
}
void push(Linkqueue &Q, int p)
{
    Qnode *q;
    q = new Qnode;
    q -> data = p;
    q -> next = NULL;
    Q.rear -> next = q;
    Q.rear = q;
}
int emptyqueue(Linkqueue Q)
{
    if(Q.front == Q.rear)
        return 1;
    else
        return 0;
}
void pop(Linkqueue &Q, int &p)
{
    Qnode *q;
    q = Q.front -> next;
    p = q -> data;
    Q.front -> next = q -> next;
    if(q == Q.rear)
        Q.rear = Q.front;
}
void bfs(Graph G,int v)
{
    int p;
    vis[v] = 1;
    Linkqueue Q;
    init(Q);
    push(Q,v);
    while(!emptyqueue(Q))
    {
        pop(Q,p);
        cout << p << '\n';
        Arcnode *q;
        q = G.vertex[p].nextArc;
        while(q != NULL)
        {
            if(!vis[q -> vertex])
            {
                vis[q -> vertex] = 1;
                push(Q,q -> vertex);
            }
            q = q -> nextArc;      //差点忘了这里
        }
    }
}
int main()
{
    memset(vis,0,sizeof(vis));
    Graph G;
    create(G);
    int v;
    cin >> v;
    bfs(G,v);
}