Submission #2501774

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Source Code Expand

#include <bits/stdc++.h>
// iostream is too mainstream
#include <cstdio>
// bitch please
#include <iostream>
#include <algorithm>
#include <cstdlib>
#include <vector>
#include <set>
#include <map>
#include <queue>
#include <stack>
#include <list>
#include <cmath>
#include <iomanip>
#include <time.h>
#define dibs reserve
#define OVER9000 1234567890
#define ALL_THE(CAKE,LIE) for(auto LIE =CAKE.begin(); LIE != CAKE.end(); LIE++)
#define tisic 47
#define soclose 1e-8
#define chocolate win
// so much chocolate
#define patkan 9
#define ff first
#define ss second
#define abs(x) ((x < 0)?-(x):x)
#define uint unsigned int
#define dbl long double
#define pi 3.14159265358979323846
using namespace std;
// mylittledoge

typedef long long cat;

#ifdef DONLINE_JUDGE
	// palindromic tree is better than splay tree!
	#define lld I64d
#endif

int main() {
	cin.sync_with_stdio(0);
	cin.tie(0);
	cout << fixed << setprecision(10);
	int N, M;
	cin >> N >> M;
	vector<int> P(N);
	vector< vector<int> > G(N);
	for(int i = 0; i < N; i++) cin >> P[i];
	for(int i = 0; i < M; i++) {
		int u, v;
		cin >> u >> v;
		G[--u].push_back(--v);
		G[v].push_back(u);
	}

	vector<int> comp(N, -1);
	int C = 0;
	for(int i = 0; i < N; i++) if(comp[i] == -1) {
		queue<int> q;
		comp[i] = C;
		q.push(i);
		while(!q.empty()) {
			ALL_THE(G[q.front()], it) if(comp[*it] == -1) {
				comp[*it] = C;
				q.push(*it);
			}
			q.pop();
		}
		C++;
	}

	vector<int> pos(N);
	for(int i = 0; i < N; i++) pos[P[i]-1] = i;
	int ans = 0;
	for(int i = 0; i < N; i++) if(comp[i] == comp[pos[i]]) ans++;
	cout << ans << "\n";
	return 0;}

// look at my code
// my code is amazing

Submission Info

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