bfs 邻接表（需要优化 可能会RE *【模板】）

//---基于邻接表的bfs 

 
#include <stdio.h> 
#include <string.h> 
#include <iostream> 
#include <string> 
#include <algorithm> 
#include <queue> 
 
using namespace std; 
 
struct node 
{ 
    int date; 
    struct node *next; 
}*head[101], *tail[101]; 
 
void bfs(int s) 
{ 
    int flag=0; //标记输出，保证输出格式的正确的 
 
    bool vis[101]; 
    memset(vis, false, sizeof(vis) ); 
    queue<int>q;    
  
    vis[s]=true; //标记起点访问 
    q.push(s); 
    int cur; 
 
    struct node *p; 
    while( !q.empty() ) 
    { 
        cur=q.front(); 
        if(flag==0) 
        { 
            printf("%d", cur ); 
            flag=1; 
        } 
        else if(flag==1) 
        { 
            printf(" %d", cur ); 
        } 
 
        q.pop(); 
        if( head[cur] ) //如果不空 
        { 
            //开始遍历 
            p=head[cur]->next; 
            while(p) 
            { 
                if(vis[p->date]==false) 
                { 
                    q.push(p->date); 
                    vis[p->date]=true; 
                } 
                p=p->next; 
            } 
        } 
    } 
    printf("
"); 
} 
 
int main() 
{ 
    int t; 
    cin>>t; 
    int n, m, s; 
    int u, v; 
    int i; 
     
    while(t--) 
    { 
        for(i=0; i<=100; i++) 
        { 
            head[i]=new struct node; 
            head[i]->next = NULL; 
            tail[i] = head[i]; 
        } 
        //邻接表的初始化 
         
        scanf("%d %d %d", &n, &m, &s) ; 
        struct node *p, *q; 
        for(i=0; i<m; i++) 
        { 
            scanf("%d %d", &u, &v ); 
            p=new struct node; 
            p->date=v; p->next=NULL; 
            q=new struct node; 
            q->date=u; q->next=NULL; 
             
            tail[u]->next=p;  tail[u]=p; 
            tail[v]->next=q;  tail[v]=q; 
        }  //建立邻接表 
        bfs(s); 
    } 
    return 0; 
}