Submission #3418240

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Source Code Expand

#include <iostream>
#include <vector>
using namespace std;

int p[100010];

int find(int n) {
	if (n == p[n]) return n;
	return p[n] = find(p[n]);
}

void merge(int a, int b) {
	a = find(a);
	b = find(b);

	if (a != b) p[b] = a;
}

int main() {
	ios::sync_with_stdio(0);
	cin.tie(0);

	int n, m;
	cin >> n >> m;

	vector<int> arr(n + 1);
	for (int i = 1; i <= n; ++i) {
		cin >> arr[i];
		p[i] = i;
	}

	int a, b;
	while (m--) {
		cin >> a >> b;
		merge(a, b);
	}

	int cnt = 0;
	for (int i = 1; i <= n; ++i) {
		if (find(i) == find(arr[i])) cnt++;
	}

	cout << cnt;
}

Submission Info

Judge Result