26 lines
735 B
C++
26 lines
735 B
C++
|
vector<bool> isbridge(m);
|
||
|
|
{
|
||
|
|
vector<int> low(n + 1), dfn(n + 1), father(n + 1);
|
||
|
|
int dfs_clock = 0;
|
||
|
|
int cnt_bridge = 0;
|
||
|
|
auto dfs = [&] (auto dfs, int u, int fa) -> void {
|
||
|
|
father[u] = fa;
|
||
|
|
low[u] = dfn[u] = ++dfs_clock;
|
||
|
|
for (auto&& [v, i] : ch[u]) {
|
||
|
|
if (!dfn[v]) {
|
||
|
|
dfs(dfs, v, u);
|
||
|
|
low[u] = min(low[u], low[v]);
|
||
|
|
if (low[v] > dfn[u]) {
|
||
|
|
isbridge[i] = true;
|
||
|
|
++cnt_bridge;
|
||
|
|
}
|
||
|
|
} else if (dfn[v] < dfn[u] && v != fa) {
|
||
|
|
low[u] = min(low[u], dfn[v]);
|
||
|
|
}
|
||
|
|
}
|
||
|
|
};
|
||
|
|
for (int i = 1; i <= n; ++i) {
|
||
|
|
if (not dfn[i]) dfs(dfs, i, 0);
|
||
|
|
}
|
||
|
|
}
|