teamnote history merge

2024fall/source/Graph/TarjanSCC.cpp

@@ -0,0 +1,32 @@
+vi adj[N];
+int in[N], c = 0;
+stack<int> p;
+bool fin[N]; int scn[N], nscc = 0;
+
+int dfs(int s)
+{
+    in[s] = ++c;
+    p.push(s);
+
+    int m = c;
+    for(auto i : adj[s])
+    {
+        if(in[i] == 0) m = min(m, dfs(i));
+        else if(!fin[i]) m = min(m, in[i]);
+    }
+
+    if(m == in[s])
+    {
+        nscc++;
+        while(p.top() != s)
+        {
+            int i = p.top(); p.pop();
+            scn[i] = nscc; fin[i] = true;
+        }
+        p.pop();
+        scn[s] = nscc; fin[s] = true;
+    }
+    return m;
+}
+
+forr(i, n) if(!fin[i]) dfs(i);