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