Merge pull request #18 from skku-npc/user/Jooyoung

Kosaraju

kosaraju.cpp

@@ -0,0 +1,37 @@
+int n;
+stack<int> st;
+vector<bool> check;
+vector<vector<int>> adj, adj_r;
+
+void dfs(int curr) {
+    check[curr] = true;
+    for (auto& next : adj[curr])
+        if (!check[next]) dfs(next);
+    st.push(curr);
+}
+vector<vector<int>> kosaraju() {
+    check.resize(n);
+    for (int i = 0; i < n; i++)
+        if (!check[i]) dfs(i);
+    check = vector<bool>(n);
+    vector<vector<int>> ret;
+    stack<int> sk;
+    vector<int> comp;
+    while (!st.empty()) {
+        int node = st.top();
+        st.pop();
+        if (check[node]) continue;
+        sk.push(node);
+        comp.clear();
+        while (!sk.empty()) {
+            int curr = sk.top();
+            sk.pop();
+            check[curr] = true;
+            comp.push_back(curr);
+            for (auto next : adj_r[curr])
+                if (!check[next]) sk.push(next);
+        }
+        ret.push_back(comp);
+    }
+    return ret;
+}