HDU 2460 Network
题解里的这段维护桥的变化量的代码是什么意思啊?\

while (q--) {
    int u, v;
    cin >> u >> v;
    if (dfn[u] < dfn[v])swap(u, v);
    while (dfn[u] > dfn[v]) {
        if (isBridge[u])sum--;
        isBridge[u] = 0;
        u = father[u];
    }
    while (u != v) {
        if (isBridge[v])sum--;
        isBridge[v] = 0;
        v = father[v];
    }
    cout << sum << endl;
}
cout << endl;

谢谢大佬