Submission #2739618

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Source Code Expand

# -*- coding: utf-8 -*-


if __name__ == '__main__':
    n = int(input())
    a = list(map(lambda x: int(x) - 1, input().split()))
    count = 0

    # See:
    # http://code-festival-2016-quala.contest.atcoder.jp/data/other/code-festival-2016-quala/editorial.pdf
    for i in range(len(a)):
        if i == a[a[i]]:
            count += 1

    print(count // 2)

Submission Info

Judge Result