From 76d705f0a26a1ccc5b72b5e9b15059b1fe469387 Mon Sep 17 00:00:00 2001
From: subcrip <contact@subc.rip>
Date: Mon, 20 May 2024 13:31:59 +0800
Subject: [PATCH] Add graph/bounded_mcmf.cc

Signed-off-by: subcrip <contact@subc.rip>
---
 graph/bounded_mcmf.cc | 39 +++++++++++++++++++++++++++++++++++++++
 1 file changed, 39 insertions(+)
 create mode 100644 graph/bounded_mcmf.cc

diff --git a/graph/bounded_mcmf.cc b/graph/bounded_mcmf.cc
new file mode 100644
index 0000000..6014a62
--- /dev/null
+++ b/graph/bounded_mcmf.cc
@@ -0,0 +1,39 @@
+struct bounded_mcmf {
+    int n, m, S, T;
+    mcmf net;
+    ll sum;
+    vector<ll> fl;
+    vector<ll> init;
+    bounded_mcmf(int n, int m) : sum(0), n(n), m(m), S(0), T(n + 1), net(n + 1), fl(m), init(n + 1) {}
+    void add_edge(int from, int to, ll low, ll high, ll cost, int edge_id = -1) {
+        if (edge_id != -1) {
+            fl[edge_id] += low;
+        }
+        net.add_edge(from, to, high - low, cost, edge_id, -1);
+        init[to] += low, init[from] -= low;
+    }
+    optional<tuple<ll, ll, vector<ll>>> run(int s, int t) {
+        for (int i = 1; i <= n; ++i) {
+            if (init[i] > 0) {
+                net.add_edge(S, i, init[i], 0, -1, -1);
+                sum += init[i];
+            } else if (init[i] < 0) {
+                net.add_edge(i, T, -init[i], 0, -1, -1);
+            }
+        }
+        net.add_edge(t, s, INFLL, 0, -1, -1);
+        if (sum != net.run(S, T).first) {
+            return nullopt;
+        } else {
+            auto [res_flow, res_cost] = net.run(s, t);
+            for (int from = 1; from <= n; ++from) {
+                for (auto&& [to, cap, flow, cost, rev, mark] : net.edges[from]) {
+                    if (mark != -1) {
+                        fl[mark] = flow;
+                    }
+                }
+            }
+            return {{res_flow, res_cost, fl}};
+        }
+    }
+};