Submission #2196330

---

Source Code Expand

using System;

public class Hello
{
    public static void Main()
    {
        var n = int.Parse(Console.ReadLine().Trim());
        string[] line = Console.ReadLine().Trim().Split(' ');
        var a = Array.ConvertAll(line, int.Parse);
        Console.WriteLine(getFriend(a));
    }
    public static int getFriend(int[] a)
    {
        var n = a.Length;
        var chk = new bool[n];
        var ret = 0;
        for (int i = 0; i < n; i++)
        {
            if (chk[i]) continue;
            var w = a[i] - 1;
            var w2 = a[w] - 1;
            if (w2 == i) { chk[w] = true; ret++; }
        }
        return ret;
    }
}

Submission Info

Judge Result