25 lines
789 B
C++
25 lines
789 B
C++
namespace tarjan {
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int cnt, scc_num, scc[MX], in[MX], low[MX];
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stack<int> s;
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bitset<MX> ins;
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void tarjan(vector<int> * G, int u) {
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low[u] = in[u] = cnt++, ins[u] = 1; s.push(u);
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for (int v : G[u]) {
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if (in[v] == -1) tarjan(G, v), low[u] = min(low[u], low[v]);
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else if (ins[v]) low[u] = min(low[u], in[v]);
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}
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if (low[u] == in[u]) {
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while (1) {
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int x = s.top(); s.pop();
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scc[x] = scc_num, ins[x] = 0;
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if (x == u) break;
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}
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++scc_num;
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}
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}
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void find_scc(vector<int> * G) {
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memset(scc, -1, sizeof scc), memset(in, -1, sizeof in);
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for (int u = 1; u <= N; ++u) if (scc[u] == -1) tarjan(G, u);
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}
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}
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