Create tarjan_scc.cpp

Changes

1 changed files (+27/-0)

• Graph/tarjan_scc.cpp (new)
  • @@ -0,0 +1,27 @@
    + int cnt, scc_num, scc[MAXN], in[MAXN], low[MAXN]; + stack<int> s; + bitset<MAXN> ins; + + void tarjan(int u) { + low[u] = in[u] = cnt++; + s.push(u); + ins[u] = 1; + for (int v : G[u]) { + if (in[v] == -1) tarjan(v), low[u] = min(low[u], low[v]); + else if (ins[v]) low[u] = min(low[u], in[v]); + } + if (low[u] == in[u]) { + while (1) { + int x = s.top(); s.pop(); + scc[x] = scc_num, ins[x] = 0; + if (x == u) break; + } + ++scc_num; + } + } + + + memset(scc, -1, sizeof scc), memset(in, -1, sizeof in); + for (int u = 1; u <= N; u++) { + if (scc[u] == -1) tarjan(u); + }