1 #include<cstdio>
 2 #include<cstring>
 3 #include<iostream>
 4 using namespace std;
 5 const int sz = sz;
 6 int n, m;
 7 int plat[sz][sz], in[sz], ans[sz];
 8 int main() {
 9     while(~scanf("%d%d", &n, &m)) {
10         memset(plat, 0, sizeof(plat));
11         memset(in, 0, sizeof(in));
12         int cnt = 0, flag = 0, x, y;
13         for(int i = 1; i <= m; i++) {
14             scanf("%d%d", &x, &y);
15             if(!plat[x][y]) {
16                 plat[x][y] = 1;
17                 in[y]++;
18             }
19         }
20         while(cnt < n) {
21             for(int i = 1; i <= n; i++) {
22                 if(in[i]==0) {
23                     in[i] = -1;
24                     ans[++cnt] = i;
25                     flag = i;
26                     break;
27                 }
28             }
29             for(int i = 1; i <= n; i++) {
30                 if(plat[flag][i]) in[i]--;
31             }
32         }
33         for(int i = 1; i < n; i++)
34             printf("%d ", ans[i]);
35         printf("%d\n", ans[n]);
36     }
37     return 0;
38 }

 1 #include<queue>
 2 #include<cstdio>
 3 #include<iostream>
 4 using namespace std;
 5 const int sz = 505;
 6 struct edge {
 7     int nxt, to;
 8 }e[sz<<1];
 9 priority_queue<int, vector<int>, greater<int> >q;
10 int n, m, x, y, num = 0, cnt = 0, in[sz], ans[sz], head[sz];
11 void add(int from, int to) {
12     in[to]++;
13     e[++num].nxt = head[from];
14     e[num].to = to;
15     head[from] = num;
16 }
17 int main() {
18     while(~scanf("%d%d", &n, &m)) {
19         for(int i = 1; i <= m; i++) {
20             scanf("%d%d", &x, &y);
21             add(x, y);
22         }
23         for(int i = 1; i <= n; i++) {
24             if(!in[i]) q.push(i);
25         }
26         while(!q.empty()) {
27             int u = q.top();
28             q.pop();
29             ans[++cnt] = u;
30             for(int i = head[u]; i; i = e[i].nxt) {
31                 int v = e[i].to;
32                 in[v]--;
33                 if(!in[v]) q.push(v);
34             }
35         }
36         for(int i = 1; i < n; i++)
37             printf("%d ", ans[i]);
38         printf("%d\n", ans[n]);
39     }
40     return 0;
41 }