Submission #2559230

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Source Code Expand

#include<bits/stdc++.h>

using namespace std;

vector<vector<int> > graph;
bitset<100000>vis;
bool connects(int a, int b){
    if(a == b) return true;
    bool ans = false;
    vis.set(a,1);
    for(int i = 0; i < graph[a].size() and !ans; i++){
        if(!vis.test(graph[a][i]))
            ans = connects(graph[a][i], b);
    }
    return ans;
}


int main(){

    ios_base::sync_with_stdio(false); cin.tie(NULL); cout.tie(NULL); cout.precision(20);


    int n, m, a, b;
    cin >> n >> m;
    vector<int>p(n);
    for(int i = 0; i < n; i++){
        cin >> p[i];
        p[i]--;
    }

    graph = vector<vector<int> >(n, vector<int>());
    for(int i = 0; i < m; i++){
        cin >> a >> b;
        a--; b--;
        graph[a].push_back(b);
        graph[b].push_back(a);
    }

    int ans = 0;
    for(int i = 0; i < n; i++){
        vis.reset();
        ans += connects(p[i], i);


    }
    cout << ans << endl;
}   

Submission Info

Judge Result