1 files changed, 7 insertions, 3 deletions
diff --git a/src/subway_map.cpp b/src/subway_map.cpp
index 408c4f0..5c99567 100644
--- a/src/subway_map.cpp
+++ b/src/subway_map.cpp

@@ -147,9 +147,13 @@ void SubwayMap::UpdateIndicators() {
        checked_paintings_.insert(painting_id);
        if (AP_GetPaintingMapping().count(painting_id)) {
-          networks_.AddLink(GD_GetSubwayItemForPainting(painting_id),
+          std::optional<int> from_id = GD_GetSubwayItemForPainting(painting_id);
-                            GD_GetSubwayItemForPainting(
+          std::optional<int> to_id = GD_GetSubwayItemForPainting(
-                                AP_GetPaintingMapping().at(painting_id)));
+              AP_GetPaintingMapping().at(painting_id));
+          if (from_id && to_id) {
+            networks_.AddLink(*from_id, *to_id);
+          }
        }
      }
    }