[백준/BFS/C++] 2606번 바이러스

https://www.acmicpc.net/problem/2606

2606번: 바이러스

#include <bits/stdc++.h>

using namespace std;

int n, m;
vector<int> v[101];
bool isVisited[101];
int result = 0;

void findVirus(){
    queue<int> q;
    q.push(1);
    isVisited[1] = true;

    while(!q.empty()){
        int front = q.front();
        q.pop();
        result++;
        for(int i=0; i<v[front].size(); i++){
            int x = v[front][i];
            if(!isVisited[x]){
                isVisited[x] = true;
                q.push(x);
            }
        }
    }
}

void input(){
    cin >> n >> m;
    for(int i=0; i<m; i++){
        int x, y;
        cin >> x >> y;
        v[x].push_back(y);
        v[y].push_back(x);
    }
}

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

    input();
    findVirus();
    cout << result - 1;

    return 0;
}