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Update graph/bounded_mcmf.cc 

Signed-off-by: subcrip <contact@subc.rip>
This commit is contained in:
subcrip 2024-05-20 14:40:25 +08:00
parent 9734205fb6
commit 5b56282a57
1 changed files with 49 additions and 5 deletions
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54
graph/bounded_mcmf.cc
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@ -4,15 +4,30 @@ struct bounded_mcmf {
ll sum; ll sum;
vector<ll> fl; vector<ll> fl;
vector<ll> init; 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) {} vector<ll> costs;
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), costs(m) {}
// handle negative loop case
void add_edge(int from, int to, ll low, ll high, ll cost, int edge_id = -1) { void add_edge(int from, int to, ll low, ll high, ll cost, int edge_id = -1) {
if (edge_id != -1) { if (cost < 0) {
fl[edge_id] += low; __add_edge(from, to, high, high, cost, -1);
__add_edge(to, from, 0, high - low, -cost, edge_id);
} else {
__add_edge(from, to, low, high, cost, edge_id);
} }
if (edge_id != -1) {
costs[edge_id] = cost;
if (cost < 0) {
fl[edge_id] += high; // RealFlow = UpperBound - Flow
} else {
fl[edge_id] += low; // RealFlow = LowerBound + Flow
}
}
}
void __add_edge(int from, int to, ll low, ll high, ll cost, int edge_id = -1) {
net.add_edge(from, to, high - low, cost, edge_id, -1); net.add_edge(from, to, high - low, cost, edge_id, -1);
init[to] += low, init[from] -= low; init[to] += low, init[from] -= low;
} }
optional<tuple<ll, ll, vector<ll>>> run(int s, int t) { void prep(int s, int t) {
for (int i = 1; i <= n; ++i) { for (int i = 1; i <= n; ++i) {
if (init[i] > 0) { if (init[i] > 0) {
net.add_edge(S, i, init[i], 0, -1, -1); net.add_edge(S, i, init[i], 0, -1, -1);
@ -22,6 +37,10 @@ struct bounded_mcmf {
} }
} }
net.add_edge(t, s, INFLL, 0, -1, -1); net.add_edge(t, s, INFLL, 0, -1, -1);
}
// min-cost max-flow
optional<tuple<ll, ll, vector<ll>>> run_mcmf(int s, int t) { // BUG: unchecked code
prep(s, t);
if (sum != net.run(S, T).first) { if (sum != net.run(S, T).first) {
return nullopt; return nullopt;
} else { } else {
@ -29,7 +48,32 @@ struct bounded_mcmf {
for (int from = 1; from <= n; ++from) { for (int from = 1; from <= n; ++from) {
for (auto&& [to, cap, flow, cost, rev, mark] : net.edges[from]) { for (auto&& [to, cap, flow, cost, rev, mark] : net.edges[from]) {
if (mark != -1) { if (mark != -1) {
fl[mark] = flow; if (costs[mark] < 0) {
fl[mark] -= flow;
} else {
fl[mark] += flow;
}
}
}
}
return {{res_flow, res_cost, fl}};
}
}
// min-cost flow
optional<tuple<ll, ll, vector<ll>>> run_mcf(int s, int t) {
prep(s, t);
auto [res_flow, res_cost] = net.run(S, T);
if (sum != res_flow) {
return nullopt;
} else {
for (int from = 1; from <= n; ++from) {
for (auto&& [to, cap, flow, cost, rev, mark] : net.edges[from]) {
if (mark != -1) {
if (costs[mark] < 0) {
fl[mark] -= flow;
} else {
fl[mark] += flow;
}
} }
} }
} }