diff --git a/ch4/maxflow.cpp b/ch4/maxflow.cpp
index 621cd33..2050be7 100644
--- a/ch4/maxflow.cpp
+++ b/ch4/maxflow.cpp
@@ -18,7 +18,7 @@ typedef pair<int, int> ii;
 const ll INF = 1e18; // INF = 1e18, not 2^63-1 to avoid overflow
 
 class max_flow {
-private:
+protected:
   int V;
   vector<edge> EL;
   vector<vi> AL;
@@ -76,7 +76,7 @@ class max_flow {
 
   // if you are adding a bidirectional edge u<->v with weight w into your
   // flow graph, set directed = false (default value is directed = true)
-  void add_edge(int u, int v, int w, bool directed = true) {
+  void add_edge(int u, int v, ll w, bool directed = true) {
     if (u == v) return;                          // safeguard: no self loop
     EL.emplace_back(u, v, w, 0);                 // u->v, cap w, flow 0
     AL[u].push_back(EL.size()-1);                // remember this index
@@ -96,7 +96,6 @@ class max_flow {
 
   ll dinic(int s, int t) {
     ll mf = 0;                                   // mf stands for max_flow
-    int iter = 0;
     while (BFS(s, t)) {                          // an O(VE^2) EK algorithm
       last.assign(V, 0);                         // important speedup
       while (ll f = DFS(s, t))                   // exhaust blocking flow
@@ -106,6 +105,35 @@ class max_flow {
   }
 };
 
+class max_flow_with_VW : public max_flow {
+private: 
+  inline int getIn(int v) { return (v << 1); }
+  inline int getOut(int v) { return (v << 1) + 1; }
+
+public:
+  max_flow_with_VW(int _V) : max_flow(2 * _V) {
+    for (int i = 0; i < _V; i++) 
+      max_flow::add_edge(getIn(i), getOut(i), INF);              // All vertices are initialised with infinite capacity
+  }
+
+  void add_vertex_weight(int v, ll w) {
+    get<2>(EL[getIn(v)]) = w;
+  }
+
+  void add_edge(int u, int v, ll w, bool directed = true) {
+    max_flow::add_edge(getOut(u), getIn(v), w);
+    if (!directed) max_flow::add_edge(getOut(v), getIn(u), w);
+  }
+
+  ll edmonds_karp(int s, int t) {
+    return max_flow::edmonds_karp(getIn(s), getOut(t));
+  }
+
+  ll dinic(int s, int t) {
+    return max_flow::dinic(getIn(s), getOut(t));
+  }
+};
+
 int main() {
   /*
   // Graph in Figure 4.24
@@ -131,5 +159,35 @@ int main() {
   // printf("%lld\n", mf.edmonds_karp(s, t));
   printf("%lld\n", mf.dinic(s, t));
 
+  printf("=====\n");
+
+  /*
+  // Sample graph with vertex capacities (source and sink have infinite capacities) 
+  5 0 4
+  5 6 7
+  2 1 5 2 3
+  1 3 10
+  1 3 4
+  1 4 10
+  0
+  */
+
+  scanf("%d %d %d", &V, &s, &t);
+  max_flow_with_VW mfvw(V);
+  for (int u = 1; u < V - 1; ++u) {
+    int w; scanf("%d", &w);
+    mfvw.add_vertex_weight(u, w);
+  }
+  for (int u = 0; u < V; ++u) {
+    int k; scanf("%d", &k);
+    while (k--) {
+      int v, w; scanf("%d %d", &v, &w);
+      mfvw.add_edge(u, v, w);                      
+    }
+  }
+
+  // printf("%lld\n", mfvw.edmonds_karp(s, t));
+  printf("%lld\n", mfvw.dinic(s, t));
+
   return 0;
 }
diff --git a/ch4/maxflow_in.txt b/ch4/maxflow_in.txt
index 8388569..6a4652b 100644
--- a/ch4/maxflow_in.txt
+++ b/ch4/maxflow_in.txt
@@ -3,3 +3,11 @@
 2 2 25 3 70
 3 0 70 3 5 1 25
 3 0 30 2 5 1 70
+
+5 0 4
+5 6 7
+2 1 5 2 3
+1 3 10
+1 3 4
+1 4 10
+0