1 files changed, 68 insertions, 0 deletions

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+#include "network_set.h"
+
+void NetworkSet::Clear() {
+  networks_.clear();
+  network_by_item_.clear();
+}
+
+int NetworkSet::AddLink(int id1, int id2) {
+  if (id2 > id1) {
+    // Make sure id1 < id2
+    std::swap(id1, id2);
+  }
+
+  if (network_by_item_.count(id1)) {
+    if (network_by_item_.count(id2)) {
+      int network_id1 = network_by_item_[id1];
+      int network_id2 = network_by_item_[id2];
+
+      networks_[network_id1].emplace(id1, id2);
+
+      if (network_id1 != network_id2) {
+        for (const auto& [other_id1, other_id2] : networks_[network_id2]) {
+          network_by_item_[other_id1] = network_id1;
+          network_by_item_[other_id2] = network_id1;
+        }
+
+        networks_[network_id1].merge(networks_[network_id2]);
+        networks_[network_id2].clear();
+      }
+
+      return network_id1;
+    } else {
+      int network_id = network_by_item_[id1];
+      network_by_item_[id2] = network_id;
+      networks_[network_id].emplace(id1, id2);
+
+      return network_id;
+    }
+  } else {
+    if (network_by_item_.count(id2)) {
+      int network_id = network_by_item_[id2];
+      network_by_item_[id1] = network_id;
+      networks_[network_id].emplace(id1, id2);
+
+      return network_id;
+    } else {
+      int network_id = networks_.size();
+      network_by_item_[id1] = network_id;
+      network_by_item_[id2] = network_id;
+      networks_.emplace_back();
+      networks_[network_id] = {{id1, id2}};
+
+      return network_id;
+    }
+  }
+}
+
+bool NetworkSet::IsItemInNetwork(int id) const {
+  return network_by_item_.count(id);
+}
+
+int NetworkSet::GetNetworkWithItem(int id) const {
+  return network_by_item_.at(id);
+}
+
+const std::set<std::pair<int, int>>& NetworkSet::GetNetworkGraph(int id) const {
+  return networks_.at(id);
+}