+/* Shortcut-1 graph
+ *
+ * A ---- (3) -----> C
+ * \ /
+ * (1)-> B --(1)
+ *
+ * This provides an example of a graph where the lowest cost path from
+ * (A) to (C) is not the path with the smallest number od edges.
+ */
+struct shortcut1_graphr {
+ struct agar_graph gr;
+};
+extern struct shortcut1_graphr shortcut1_graphr;
+static const struct adjacency_listr shortcut1_adjacencyr[] = {
+ {1, {3, 2}},
+ {2, {3}},
+ {3, {}},
+ {},
+};
+
+/* Shortcut-2 graph
+ *
+ * A ---- (2) -----> C
+ * \ /
+ * (2)-> B --(-1)
+ *
+ * This provides an example of a graph with a negative edge cost, but
+ * no negative cost cycles (and so still with well defined shortest
+ * paths).
+ */
+struct shortcut2_graphr {
+ struct agar_graph gr;
+};
+extern struct shortcut2_graphr shortcut2_graphr;
+static const struct adjacency_listr shortcut2_adjacencyr[] = {
+ {1, {3, 2}},
+ {2, {3}},
+ {3, {}},
+ {},
+};
+
+/* Negacycle graph
+ *
+ * A <---- (-3) ----- C
+ * \ ^
+ * (1)-> B -- (1)-/
+ *
+ * Graph with a negative length cycle, and so lacking well-defined shortest paths.
+ */
+struct negacycle_graphr {
+ struct agar_graph gr;
+};
+extern struct negacycle_graphr negacycle_graphr;
+static const struct adjacency_listr negacycle_adjacencyr[] = {
+ {1, {2}},
+ {2, {3}},
+ {3, {1}},
+ {},
+};
+