基于图的广度优先搜索策略（耿7.11）--------西工大noj.20

目录

代码

---

代码

#include <stdio.h>
#include <stdlib.h>
#include <string.h>
typedef struct ArcNode{
    int to;
    struct ArcNode *next;
    int w;
}ArcNode;
typedef struct VertexNode
{
    int data;
    ArcNode *arc;
}VertexNode;
typedef struct Graph
{
    int max;
    VertexNode *vertex;
}Graph;

//这是全局变量
int dream;
int find;

//这个是手写的队列
typedef struct QNode{
    int data;
    struct QNode*next;
}QNode;
typedef struct Queue{
    QNode*head, *tail;
}Queue;
Queue *Create_Queue()
{
    Queue *Q = (Queue*)malloc(sizeof(Queue));
    Q->tail = NULL;
    Q->head = NULL;
    return Q;
}
int Empty(Queue*Q)
{
    if(Q->head)
        return 0;
    else
        return 1;
}
void Push(Queue* Q,int  x)
{
    QNode*s = (QNode*)malloc(sizeof(QNode));
    s->data = x;
    s->next = NULL;
    if(Empty(Q))
    {
        Q->head = s;
        Q->tail = s;
    }
    else
    {
        Q->tail->next = s;
        Q->tail = s;
    }
}
int Top(Queue*Q)
{
    return Q->head->data;
}
void Pop(Queue*Q)
{
    QNode* d = Q->head;
    Q->head = Q->head->next;
    free(d);
}
Graph *Create(int n)
{
    Graph *G = (Graph*)malloc(sizeof(Graph));
    G->max = n;
    G->vertex = (VertexNode*)calloc(n+1,sizeof(VertexNode));
    for(int i = 0; i <= n; i++)
    {
        G->vertex[i].arc = NULL;
    }
    return G;
}
int Locate(Graph *G,int x)
{
    int i = 1;
    for(; i<=G->max; i++)
    {
        if(G->vertex[i].data == x)
            break;
    }
    if(i > G->max)
        return -1;
    else
        return i;
}
void Fill_VertexNode(Graph *G, int n)
{
    for(int i = 1; i <= n; i++)
    {
        scanf("%d",&G->vertex[i].data);
    }
}
void Add(Graph *G,int x, int y)
{
    int a = Locate(G,x);
    int b = Locate(G,y);
    ArcNode *A = (ArcNode*)malloc(sizeof(ArcNode));
    A->to = b;
    A->next = G->vertex[a].arc;
    G->vertex[a].arc = A;
}
void BFS(Graph* G,int * arr, int x)
{
    if(arr[x])
        return;
    Queue *Q = Create_Queue();
    Push(Q,x);
    while(!Empty(Q))
    {
        int t = Top(Q);
        Pop(Q);
        if(G->vertex[t].data == dream)
        {
            find = 1;
            return;
        }
        for(ArcNode *A = G->vertex[t].arc; A; A = A->next)
        {
            if(arr[A->to])
                continue;
            Push(Q,A->to);
        }
    }
}
int BFS_search(Graph*G, int x,int dre)
{
    find = 0;
    x = Locate(G,x);
    dream = dre;
    int *arr = (int *)calloc(G->max+1, sizeof(int));
    for(int i = 0; i <= G->max; i++)
    {
        arr[i] = 0;
    }
    BFS(G,arr,x);
    return find;
}
int main()
{
    int begin, end;
    int n,m;
    scanf("%d%d",&n,&m);
    Graph *G = Create(n);
    Fill_VertexNode(G,n);
    for(int i = 1; i <= m; i++)
    {
        int x,y;
        scanf("%d%d",&x,&y);
        Add(G,x,y);
    }
    scanf("%d%d",&begin,&end);
    int ret = BFS_search(G,begin,end);
    if(ret) printf("yes");
    else printf("no");
    return 0;
}
/*
4 4
4 2 1 3
1 2
1 3
1 4
2 3
2 3

*/