contest-10235.cpp

//Be Name Khoda
#include <bits/stdc++.h>
using namespace std;
typedef long long ll;
typedef long double ld;
const int MOD = (int)1e9 + 7;
const int MAXN = (int)2e5 + 7;
const ll inf = (ll)1e18;
const int infint = (int)2e9;
int a[MAXN], b[MAXN], out[MAXN], visited[MAXN], c[MAXN], indx[MAXN];
int comp = 0;
int main()
{
	ios::sync_with_stdio(false);
	cin.tie(0); cout.tie(0);
	int n;
	cin >> n;
	for (int i = 0; i < n; i++)
	{
		cin >> a[i];
		indx[a[i]] = i;
	}
	for (int i = 0; i < n; i++)
	{
		cin >> b[i];
		out[a[i]] = b[i];
	}
	for (int i = 0; i < n; i++)
		cin >> c[i];
	vector<int> first;
	for (int i = 1; i <= n; i++)
	{
		if(!visited[i])
		{
			int root = -1, j = i;
			comp++;
			vector<int> all;
			all.push_back(j);
			visited[j] = comp;
			
			while(!visited[out[j]])
			{
				all.push_back(out[j]);
				visited[out[j]] = comp;
				j = out[j];
			}
			j = out[j];
			if(visited[j] < comp)
				continue;
			//cout << j << "\n";
			int ind = -1;
			for (int k = 0; k < all.size(); k++)
			{
				if(all[k] == j)
				{
					ind = k;
				}
				if(ind != -1)
					first.push_back(all[k]);
			}
		}
	}
	fill(out, out + MAXN, -1);
	fill(visited, visited + MAXN, 0);
	comp = 0;
	for (int i = 0; i < first.size(); i++)
		out[first[i]] = c[indx[first[i]]];
	int ans1 = 0;
	for (auto i : first)
	{
		if(!visited[i])
		{
			int root = -1, j = i;
			comp++;
			vector<int> all;
			all.push_back(j);
			visited[j] = comp;
			
			while(out[j] != 0 and !visited[out[j]])
			{
				all.push_back(out[j]);
				visited[out[j]] = comp;
				j = out[j];
			}
			j = out[j];
			if(visited[j] < comp or out[j] == 0)
				continue;
			//cout << j << "\n";
			int ind = -1;
			for (int k = 0; k < all.size(); k++)
			{
				if(all[k] == j)
				{
					ind = k;
					break;
				}
			}
			ans1 += all.size() - ind;
		}
	}
	cout << n - ans1;
}