From 897bab12bf05fb0bbe51fb151fa7b9ef38840e32 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Stefan=20M=C3=BCller?= <stefan.mueller@aksdb.de>
Date: Wed, 14 May 2025 20:53:39 +0200
Subject: [PATCH] Change Dijkstra's algorithm to return all shortest distances

---
 include/aoc/common/WeightedEdgeGraph.hpp |  2 +-
 src/common/WeightedEdgeGraph.cpp         | 21 +++++++--------------
 2 files changed, 8 insertions(+), 15 deletions(-)

diff --git a/include/aoc/common/WeightedEdgeGraph.hpp b/include/aoc/common/WeightedEdgeGraph.hpp
index be1c0bd..2c7961d 100644
--- a/include/aoc/common/WeightedEdgeGraph.hpp
+++ b/include/aoc/common/WeightedEdgeGraph.hpp
@@ -28,7 +28,7 @@ class WeightedEdgeGraph
     void addEdge(const int vertex1, const int vertex2, const int weight);
     int getVertexWeight(const int vertex) const;
     int getEdgeWeight(const int edge) const;
-    int dijkstra(const int source, const int target) const;
+    std::vector<int> dijkstra(const int source) const;
 
     struct Incidence
     {
diff --git a/src/common/WeightedEdgeGraph.cpp b/src/common/WeightedEdgeGraph.cpp
index 474704a..9f29fe0 100644
--- a/src/common/WeightedEdgeGraph.cpp
+++ b/src/common/WeightedEdgeGraph.cpp
@@ -49,7 +49,7 @@ int WeightedEdgeGraph::getEdgeWeight(const int edge) const
     return edgeWeights_[edge];
 }
 
-int WeightedEdgeGraph::dijkstra(const int source, const int target) const
+std::vector<int> WeightedEdgeGraph::dijkstra(const int source) const
 {
     std::vector<int> distances(firstVertexIncidences_.size(), std::numeric_limits<int>::max());
     auto compare = [&distances](int left, int right) { return distances[left] > distances[right]; };
@@ -63,25 +63,18 @@ int WeightedEdgeGraph::dijkstra(const int source, const int target) const
         int v{ queue.top() };
         queue.pop();
 
-        int incidence{ firstVertexIncidences_[v] };
-        while (incidence > -1)
+        for (auto neighbor = begin(v); neighbor != end(); ++neighbor)
         {
-            int neighbor{ vertexEdgeIncidences_[incidence].vertex };
-            int newDistance{ distances[v] + edgeWeights_[incidence >> 1] };
-            if (distances[neighbor] > newDistance)
+            int newDistance{ distances[v] + edgeWeights_[neighbor->edge] };
+            if (distances[neighbor->vertex] > newDistance)
             {
-                distances[neighbor] = newDistance;
-                queue.push(neighbor);
+                distances[neighbor->vertex] = newDistance;
+                queue.push(neighbor->vertex);
             }
-            if (neighbor == target)
-            {
-                return distances[target];
-            }
-            incidence = vertexEdgeIncidences_[incidence].next;
         }
     }
 
-    return -1;
+    return distances;
 }
 
 WeightedEdgeGraph::NeighborIterator WeightedEdgeGraph::begin(const int vertex) const