(prim) fix inverted edge cost calculation

cvvergara · cvvergara · commit 4912a28f6ce9 · 2026-02-23T14:41:36.000-06:00
diff --git a/include/spanningTree/prim.hpp b/include/spanningTree/prim.hpp
@@ -131,7 +131,7 @@ class Pgr_prim : public Pgr_mst<G> {
               */
              if (u == v) continue;
 
-             auto cost = distances[u] - distances[v];
+             auto cost = distances[v] - distances[u];
              auto edge = graph.get_edge(u, v, cost);
              this->m_spanning_tree.edges.insert(edge);
          }

Original file line number	Diff line number	Diff line change
`@@ -131,7 +131,7 @@ class Pgr_prim : public Pgr_mst<G> {`
`131`	`131`	`*/`
`132`	`132`	`if (u == v) continue;`
`133`	`133`
`134`		`- auto cost = distances[u] - distances[v];`
	`134`	`+ auto cost = distances[v] - distances[u];`
`135`	`135`	`auto edge = graph.get_edge(u, v, cost);`
`136`	`136`	`this->m_spanning_tree.edges.insert(edge);`
`137`	`137`	`}`