diff options
Diffstat (limited to 'graph/scc.cpp')
| -rw-r--r-- | graph/scc.cpp | 54 |
1 files changed, 54 insertions, 0 deletions
diff --git a/graph/scc.cpp b/graph/scc.cpp new file mode 100644 index 0000000..b33616b --- /dev/null +++ b/graph/scc.cpp @@ -0,0 +1,54 @@ +int counter, sccCounter, n; //n == number of vertices +vector<bool> visited, inStack; +vector< vector<int> > adjlist; +vector<int> d, low, sccs; +stack<int> s; + +void visit(int v) { + visited[v] = true; + d[v] = counter; + low[v] = counter; + counter++; + inStack[v] = true; + s.push(v); + + for (int i = 0; i < (int)adjlist[v].size(); i++) { + int u = adjlist[v][i]; + if (!visited[u]) { + visit(u); + low[v] = min(low[v], low[u]); + } else if (inStack[u]) { + low[v] = min(low[v], low[u]); + } + } + + if (d[v] == low[v]) { + int u; + do { + u = s.top(); + s.pop(); + inStack[u] = false; + sccs[u] = sccCounter; + } while(u != v); + sccCounter++; + } +} + +void scc() { + //read adjlist + + visited.clear(); visited.assign(n, false); + d.clear(); d.resize(n); + low.clear(); low.resize(n); + inStack.clear(); inStack.assign(n, false); + sccs.clear(); sccs.resize(n); + + counter = 0; + sccCounter = 0; + for (i = 0; i < n; i++) { + if (!visited[i]) { + visit(i); + } + } + //sccs has the component for each vertex +}
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