rename files based on their classes

include/graph_distances.hpp

@@ -0,0 +1,24 @@
+#ifndef DISTANCE_HPP_
+#define DISTANCE_HPP_
+
+#include <cstddef>
+#include <vector>
+
+class graph_distances
+{
+public:
+    std::vector<int> distances;          // distances[n] = distance from node n to target
+    std::vector<size_t> parents;         // parents[n] = next node on the path from node n to target
+    std::vector<size_t> nearest_targets; // nearest_target[n] = closest target node to  node n
+
+public:
+    auto clear() -> void;
+    [[nodiscard]] auto empty() const -> bool;
+
+    auto calculate_distances(size_t node_count, const std::vector<std::pair<size_t, size_t>>& edges,
+                             const std::vector<size_t>& targets) -> void;
+
+    [[nodiscard]] auto get_shortest_path(size_t source) const -> std::vector<size_t>;
+};
+
+#endif