27 lines
519 B
Python
27 lines
519 B
Python
import sys
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from collections import deque
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input = sys.stdin.readline
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N, M = map(int, input().split())
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A = [[] for _ in range(N+1)]
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indegree = [0] * (N+1)
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for i in range(M):
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S, E = map(int, input().split())
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A[S].append(E)
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indegree[E] += 1
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queue = deque()
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for i in range(1, N+1):
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if indegree[i] == 0:
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queue.append(i)
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while queue:
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now = queue.popleft()
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print(now, end=' ')
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for next in A[now]:
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indegree[next]-=1
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if indegree[next] == 0:
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queue.append(next) |