39 lines
989 B
Python
39 lines
989 B
Python
import sys
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input = sys.stdin.readline
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class TopoSort:
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def __init__(self, N, E):
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self.__N = N
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self.__edges = E
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self.__targets = [[] for _ in range(self.__N)]
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self.__indeg = [0] * self.__N
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for u, v in self.__edges:
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self.__indeg[v] += 1
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self.__targets[u].append(v)
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def sort(self) -> list[int]:
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indeg = self.__indeg.copy()
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Q = []
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for i, d in enumerate(indeg):
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if d == 0:
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Q.append(i)
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line = []
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while Q:
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u = Q.pop()
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line.append(u)
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for v in self.__targets[u]:
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indeg[v] -= 1
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if indeg[v] == 0:
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Q.append(v)
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return line
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if __name__ == "__main__":
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N, M = map(int, input().split())
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E = [tuple(map(lambda x: int(x) - 1, input().split())) for _ in range(M)]
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solver = TopoSort(N, E)
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print(" ".join(map(lambda x: str(int(x) + 1), solver.sort())))
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