[Algorithm] Baekjoon 2644번 : 촌수계산

https://www.acmicpc.net/problem/2644

2644번: 촌수계산

struct Node
{
    int node;
    int count;
};
 
vector<vector<int>> graph(101);
bool visited[101];
 
int BFS(int start, int target)
{
    queue<Node> q;
    q.push({ start,0 });
    visited[start] = true;
 
    while (!q.empty())
    {
        int curNode = q.front().node;
        int curCount = q.front().count;
        q.pop();
 
        if (curNode == target)
        {
            return curCount;
        }
 
        for (int i = 0; i < graph[curNode].size(); ++i)
        {
            int nextNode = graph[curNode][i];
            
            if (visited[nextNode]) continue;
            q.push({ nextNode,curCount + 1 });
            visited[nextNode] = true;
        }
    }
 
    return -1;
}
 
int main()
{
    ios::sync_with_stdio(false);
    cin.tie(0);
    cout.tie(0);
 
    int n, s, e, m;
    int a, b;
 
    cin >> n >> s >> e >> m;
 
    for (int i = 0; i < m; ++i)
    {
        cin >> a >> b;
 
        graph[a].push_back(b);
        graph[b].push_back(a);
    }
 
    cout << BFS(s, e);
}