init

1E.py

@@ -0,0 +1,25 @@
+n, m = map(int, input().split())
+adj = [[] for _ in range(n + 1)]
+in_degree = [0] * (n + 1)
+for _ in range(m):
+    u, v = map(int, input().split())
+    adj[u].append(v)
+    in_degree[v] += 1
+q = []
+for i in range(1, n + 1):
+    if in_degree[i] == 0:
+        q.append(i)
+head = 0
+topsort = []
+while head < len(q):
+    u = q[head]
+    head += 1
+    topsort.append(u)    
+    for v in adj[u]:
+        in_degree[v] -= 1
+        if in_degree[v] == 0:
+            q.append(v)
+if len(topsort) == n:
+    print(*topsort)
+else:
+    print("-1")