Submission #33674915

Source Code Expand

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def main(N, a):
    a = [None] + a
    pat = 0
    same = 0
    for i in range(1, N+1):
        if a[i] == i: same += 1
        elif a[a[i]] == i: pat += 1
        
    return same * (same-1) // 2 + pat // 2
N = int(input())
*a, = map(int, input().split())
print(main(N, a))
 
 
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def main(N, a):
    a = [None] + a
    pat = 0
    same = 0
    for i in range(1, N+1):
        if a[i] == i: same += 1
        elif a[a[i]] == i: pat += 1
        
    return same * (same-1) // 2 + pat // 2

N = int(input())
*a, = map(int, input().split())

print(main(N, a))

Submission Info

Judge Result