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1766.py
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1766.py
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import sys
from collections import deque
import heapq
class Node():
def __init__(self, n):
self.number = n
self.linkfrom = []
self.linkto = []
self.fromcount = 0
def __gt__(self, value):
if self.fromcount == value.fromcount:
return self.number > value.number
else:
return self.fromcount > value.fromcount
def __str__(self):
return str(self.number)
N, M = [int(x) for x in input().split()]
students = [Node(int(x)) for x in range(N+1)]
students[0].fromcount = -1
for i in range(M):
X, Y = [int(x) for x in input().split()]
students[X].linkto.append(students[Y])
students[Y].linkfrom.append(students[X])
students[Y].fromcount += 1
disQ = []
resultQ = deque()
tpsort = deque()
for s in students:
if s.fromcount == 0:
heapq.heappush(disQ, (s.fromcount, s))
while disQ:
fromcount, node = heapq.heappop(disQ)
tpsort.append(node)
for child in node.linkto:
child.fromcount -= 1
if child.fromcount == 0:
heapq.heappush(disQ, (child.fromcount, child))
print(" ".join([str(x) for x in tpsort]))