Submission #2561026

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Source Code Expand

#include <iostream>
#include <vector>
#include <algorithm>
#include <functional>

using namespace std;

int root[100000];
int getRoot(int v){ return root[v] == -1 ? v : root[v] = getRoot(root[v]); }

int main(){
	int N, M;
	while(cin >> N >> M){
		vector<int> p(N);
		for(auto& t : p){ cin >> t; --t; }
		fill(root, root+N, -1);
		for(int i=0;i<M;i++){
			int x, y;
			cin >> x >> y;
			--x; --y;
			int p = getRoot(x);
			int q = getRoot(y);
			if(p != q) root[q] = p;
		}
		int res = 0;
		for(int i=0;i<N;i++){
			if(getRoot(i) == getRoot(p[i])) ++res;
		}
		cout << res << endl;
	}
}

Submission Info

Judge Result