PATA1013_连通图（难度：⭐️⭐️⭐️）

需要修补的路就是连通图数量 - 1.

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#include <bits/stdc++.h>
using namespace std;
vector<vector<int>> v;
bool vis[1010];
void DFS (int s) {
    if (vis[s] == true) return;
    vis[s] = true;
    for (int i = 0; i < v[s].size(); i++) {
        int now = v[s][i];
        if(vis[now] == false) DFS (now);
    }
    return;
}
int main() {
    int n, m, k, a, b, occupy;
    scanf ("%d %d %d", &n, &m, &k);
    v.resize(n + 1);
    for (int i = 0; i < m; i++) {
        scanf ("%d %d", &a, &b);
        v[a].push_back(b);
        v[b].push_back(a);
    }
    for (int i = 0; i < k; i++) {
        int cnt = 0;
        scanf ("%d", &occupy);
        // cout << occupy << endl;
        fill (vis, vis + 1010, false);
        vis[occupy] = true;
        for (int j = 1; j <= n; j++) {
            if (j != occupy && vis[j] == false) {
                DFS (j);
                cnt++;
            }
        }
        cout << cnt - 1 << endl;
    }
}