Add graph/examples/passive_flow_with_demands.cc

Signed-off-by: subcrip <contact@subc.rip>

graph/examples/passive_flow_with_demands.cc

@@ -0,0 +1,77 @@
+// ...
+
+#define SINGLE_TEST_CASE
+// #define DUMP_TEST_CASE 7219
+// #define TOT_TEST_CASE 10000
+
+void dump() {}
+
+void dump_ignore() {}
+
+void prep() {
+}
+
+struct dinic {
+    // ...
+};
+
+void solve() {
+    read(int, n, m);
+    dinic net(n + 1);
+    vector<int> init(n + 1);
+    vector<int> res(m);
+    for (int i = 0; i < m; ++i) {
+        read(int, u, v, lower, upper);
+        net.add_edge(u, v, upper - lower, i, -1);
+        init[v] += lower;  // in
+        init[u] -= lower;  // out
+        res[i] += lower;
+    }
+    for (int i = 1; i <= n; ++i) {
+        if (init[i] > 0) {
+            net.add_edge(0, i, init[i], -1, -1);
+        } else if (init[i] < 0) {
+            net.add_edge(i, n + 1, -init[i], -1, -1);
+        }
+    }
+    net.run(0, n + 1);
+    for (auto&& [from, e] : enumerate(net.edges)) {
+        for (auto&& [to, cap, flow, rev, mark] : e) {
+            if ((from == 0 or to == n + 1) and flow != cap) {
+                cout << "NO\n";
+                return;
+            }
+            if (mark != -1) {
+                res[mark] += flow;
+            }
+        }
+    }
+    cout << "YES\n";
+    copy(res.begin(), res.end(), oi<int>(cout, "\n"));
+}
+
+int main() {
+#if __cplusplus < 201703L || defined(_MSC_VER) && !defined(__clang__)
+    assert(false && "incompatible compiler variant detected.");
+#endif
+    untie, cout.tie(NULL);
+    prep();
+#ifdef SINGLE_TEST_CASE
+    solve();
+#else
+    read(int, t);
+    for (int i = 0; i < t; ++i) {
+#ifdef DUMP_TEST_CASE
+        if (t != (TOT_TEST_CASE)) {
+            solve();
+        } else if (i + 1 == (DUMP_TEST_CASE)) {
+            dump();
+        } else {
+            dump_ignore();
+        }
+#else
+        solve();
+#endif
+    }
+#endif
+}