1 /*
2 题意：中文题
3
4 题解：拓扑排序
5 */
6 #include <cstdio>
7 #include <cstring>
8
9 #define MAXN 505
10 int toposort(int n,int mat[][MAXN],int* ret){
11 int d[MAXN],i,j,k;
12 for (i=0;i<n;i++)
13 for (d[i]=j=0;j<n;d[i]+=mat[j++][i]);
14 for (k=0;k<n;ret[k++]=i){
15 for (i=0;d[i]&&i<n;i++);
16 if (i==n)
17 return 0;
18 for (d[i]=-1,j=0;j<n;j++)
19 d[j]-=mat[i][j];
20 }
21 return 1;
22 }
23
24 int ans[MAXN];
25 int gra[MAXN][MAXN];
26
27 int main(void)
28 {
29 int n,m;
30 while (~scanf("%d%d",&n,&m))
31 {
32 memset(gra,0,sizeof(gra));
33 while (m--)
34 {
35 int p1,p2;
36 scanf("%d%d",&p1,&p2);
37 p1--;
38 p2--;
39 gra[p1][p2] = 1;
40 }
41 toposort(n,gra,ans);
42 printf("%d",ans[0]+1);
43 for(int i=1; i<n; i++)
44 printf(" %d",ans[i]+1);
45 printf("\n");
46 }
47 return 0;
48 }
