Create StronglyConnectedComponents.cpp

C-Plus-Plus/StronglyConnectedComponents.cpp

@@ -0,0 +1,65 @@
+/*
+  Strongly Connected Components
+  Author: Johnny Villegas
+  Github: Jvillegasd
+*/
+
+#include <bits/stdc++.h>
+
+using namespace std;
+
+int NUM_NODES = 100
+vector<int> g[NUM_NODES], rg[NUM_NODES];
+bool visited[NUM_NODES];
+stack<int> s;
+
+void DFS(int u) {
+  visited[u] = true;
+  for(auto v : g[u]) {
+    if (!visited[v]) {
+      DFS(v);
+    }
+  }
+  s.push(u);
+}
+
+void DFS_inv(int u) {
+  visited[u] = true;
+  print("Node: %d\n", u);
+  for(auto v : rg[u]) {
+    if (!visited[v]) {
+      DFS_inv(v);
+    }
+  }
+}
+
+void SCC() {
+  int comp = 1;
+  for (int u = 1; u <= NUM_NODES; u++) {
+    if (!visited[u]) {
+      DFS(u);
+    }
+  }
+  memset(visited, 0, sizeof(visited));
+  while(!s.empty()) {
+    int u = s.top();
+    s.pop();
+    if (visited[u]) {
+      continue;
+    }
+    printf("Component #%d:\n", comp++);
+    DFS_inv(u);
+    printf("\n");
+  }
+}
+
+int main() {
+  /*
+    This is the SCC Kosajaru algorithm. Before to run it, you have to 
+    fill DAG "g" and its reverse "rg". Reverse DAG is the same DAG "g" but
+    edges are pointing to oppposite direction.
+  */
+
+  SCC();
+  return 0;
+}