1 #include <stdio.h>
 2 #include <string.h>
 3 #include <iostream>
 4 #include <algorithm>
 5 #include <vector>
 6 #include <queue>
 7 using namespace std;
 8 #define maxx 30010
 9 vector <int > vec[maxx];
10 priority_queue <int > q;  //优先队列
11 int num[maxx],in[maxx];
12 int main ()
13 {
14     int t,u,v,m,n,i,j;
15     scanf("%d",&t);
16     while (t --)
17     {
18         scanf("%d%d",&n,&m);
19         for (i = 1; i <= n; i ++)  //清空容器内的数据
20             vec[i].clear();
21         memset(in,0,sizeof(in));   //入度初始化为0
22 
23         for (i = 0; i < m; i ++)
24         {
25             scanf("%d%d",&u,&v);
26             in[u] ++;
27             vec[v].push_back(u);
28         }
29         for (i = 1; i <= n; i ++)   //将入度为0的点加入优先队列
30             if (in[i]==0) q.push(i);
31 
32         j = 0;
33         while(!q.empty())
34         {
35             int k = q.top();
36             q.pop();
37             num[j ++] = k;
38             int len = vec[k].size();
39             for (i = 0; i < len; i ++)  // 删除与度数为0的节点相关联的边
40             {
41                 int l = vec[k][i];
42                 in[l] --;
43                 if (in[l]==0)
44                     q.push(l);
45             }
46         }
47         for (i = j-1; i >= 0; i --)
48         {
49             if (i==0)
50                 printf("%d",num[i]);
51             else
52                 printf("%d ",num[i]);
53         }
54         printf("\n");
55     }
56     return 0;
57 }