[백준] 바이러스 c++

 

 

Code

#include<iostream>
#include<vector>
#include<algorithm>
#include<string>
#include<stack>
#include<queue>
#include<map>
using namespace std;
int answer;
int m, n;
bool visited[101];
vector<vector<int>> v(101);
 
void dfs(int node) {
    visited[node] = true;
    for (int i = 0; i < v[node].size(); i++) {
        int next = v[node][i];
 
        if (!visited[next])
            dfs(next);
    }
}
 
int main()
{
    cin >> m;
    cin >> n;
    for (int i = 0; i < n; i++) {
        int node1, node2;
        cin >> node1 >> node2;
        v[node1].push_back(node2);
        v[node2].push_back(node1);
    }
    dfs(1);
 
    for (int i = 0; i < 101; i++) {
        if (visited[i])
            answer++;
    }
    
    //자신 제외
    cout << answer-1;
}