题解 | 【模板】拓扑排序

import sys

n, m = map(int, input().split(' '))
indegree = [0 for i in range(n + 1)]
vis = [0 for i in range(n + 1)]
indegree[0] = 100
edg = [[]for i in range(n + 1)]
for zzz in range(m):
    x, y = map(int, input().split(' '))
    indegree[y] += 1
    edg[x].append(y)
nodes = []

res = []

for i in range(n + 1):
    if indegree[i] == 0:
        nodes.append(i)
while nodes:
    t = nodes.pop()
    vis[t] = 1
    res.append(str(t))
    for v in edg[t]:
        indegree[v] -= 1
        if indegree[v] == 0:
            nodes.append(v)
if sum(vis) < n:
    print(-1)
else:
    print(' '.join(res))
    

没什么好说的，模板题，注意n=0还有要遍历到for i in range(n+1)，这两个点坑了我