Submission #1171900

#	Time	Username	Problem	Language	Result	Execution time	Memory
1171900		Isam	Naboj (COCI22_naboj)	Pypy 3	110 / 110	712 ms	91920 KiB

naboj

from collections import deque

def main():
    n, m = map(int, input().split())
    
    cnt = [0] * (n + 1)
    g = [[] for _ in range(n + 1)]
    em = []
    q = deque()
    
    for _ in range(m):
        a, b = map(int, input().split())
        g[b].append(a)
        cnt[a] += 1
    
    for i in range(1, n + 1):
        if cnt[i] == 0:
            q.append(i)
    
    while q:
        cur = q.popleft()
        em.append(cur)
        
        for to in g[cur]:
            cnt[to] -= 1
            if cnt[to] == 0:
                q.append(to)
    
    if len(em) != n:
        print(-1)
    else:
        print(n)
        for to in em:
            print(to, 1)

if __name__ == "__main__":
    main()

Compilation message (stdout)

Compiling 'naboj.py'...

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  adding: __main__.pyc (deflated 33%)

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• Subtask 1: 15 / 15
• Subtask 2: 25 / 25
• Subtask 3: 70 / 70