Course Schedule

import sys
from collections import deque

inp = sys.stdin.read().split()

n,m = int(inp[0]),int(inp[1])

adj = [[] for _ in range(n+1)]
in_degree = [0] * (n + 1)

for i in range(m):
    a = int(inp[2+ i*2])
    b = int(inp[3 +  i*2])
    adj[a].append(b)
    in_degree[b] +=1



#kahn's algorithm
queue = deque()
for i in range(1, n + 1):
    if in_degree[i] == 0: #indegree = 0 which means we can add them right away since they odnt depend on any course
        queue.append(i)

order = []
while queue:
    node = queue.popleft()
    order.append(node)
    for neighb in adj[node]:
        in_degree[neighb] -=1
        if in_degree[neighb] == 0:
            queue.append(neighb)

if len(order)==n:
    #we got all of em
    print(*(order))
else:
    print("IMPOSSIBLE")

Test 1

Verdict: ACCEPTED

Test 2

Verdict: ACCEPTED

Test 3

Verdict: ACCEPTED

Test 4

Verdict: ACCEPTED

Test 5

Verdict: ACCEPTED

Test 6

Verdict: ACCEPTED

Test 7

Verdict: ACCEPTED

Test 8

Verdict: ACCEPTED

Test 9

Verdict: ACCEPTED

Test 10

Verdict: ACCEPTED

Test 11

Verdict: ACCEPTED

Test 12

Verdict: ACCEPTED

Test 13

Verdict: ACCEPTED

Test 14

Verdict: ACCEPTED

Test 15

Verdict: ACCEPTED

Test 16

Verdict: ACCEPTED

Test 17

Verdict: ACCEPTED