71 lines
2.5 KiB
C
71 lines
2.5 KiB
C
#include "c_Test.h"
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#include "c_EdgeWeightedDigraph.h"
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#include "c_BellmanFordSP.h"
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TEST_CASE(test_bellman_ford_shortest_path_negative_weights) {
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c_EdgeWeightedDigraph_t g;
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c_EdgeWeightedDigraph_Init(&g, 4, NULL);
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/* Construct a graph with negative weights but NO negative cycles:
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* 0 -> 1 (Weight: 5.0)
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* 0 -> 2 (Weight: 2.0)
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* 2 -> 1 (Weight: -4.0) -> Shortest path to 1 is 0->2->1 (Total: -2.0)
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* 1 -> 3 (Weight: 3.0) -> Shortest path to 3 is 0->2->1->3 (Total: 1.0)
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*/
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c_EdgeWeightedDigraph_AddEdge(&g, 0, 1, 5.0);
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c_EdgeWeightedDigraph_AddEdge(&g, 0, 2, 2.0);
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c_EdgeWeightedDigraph_AddEdge(&g, 2, 1, -4.0);
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c_EdgeWeightedDigraph_AddEdge(&g, 1, 3, 3.0);
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c_BellmanFordSP_t sp;
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c_err_t err = c_BellmanFordSP_Init(&sp, &g, 0, &g.allocator);
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ASSERT_INT_EQ(C_SUCCESS, err);
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ASSERT_FALSE(c_BellmanFordSP_HasNegativeCycle(&sp));
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ASSERT_TRUE(c_BellmanFordSP_HasPathTo(&sp, 3));
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ASSERT_DOUBLE_EQ_MSG(-2.0, c_BellmanFordSP_DistTo(&sp, 1), "Shortest path to 1 wrong");
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ASSERT_DOUBLE_EQ_MSG(1.0, c_BellmanFordSP_DistTo(&sp, 3), "Shortest path to 3 wrong");
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c_BellmanFordSP_Destroy(&sp);
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c_EdgeWeightedDigraph_Destroy(&g);
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}
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TEST_CASE(test_bellman_ford_negative_cycle_detection) {
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c_EdgeWeightedDigraph_t g;
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c_EdgeWeightedDigraph_Init(&g, 3, NULL);
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/* Construct a graph with a negative cycle loop:
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* 0 -> 1 (Weight: 2.0)
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* 1 -> 2 (Weight: -1.0)
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* 2 -> 1 (Weight: -2.0) -> Cycle 1->2->1 has total weight -3.0 (Negative Cycle!)
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*/
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c_EdgeWeightedDigraph_AddEdge(&g, 0, 1, 2.0);
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c_EdgeWeightedDigraph_AddEdge(&g, 1, 2, -1.0);
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c_EdgeWeightedDigraph_AddEdge(&g, 2, 1, -2.0);
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c_BellmanFordSP_t sp;
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c_err_t err = c_BellmanFordSP_Init(&sp, &g, 0, &g.allocator);
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ASSERT_INT_EQ(C_SUCCESS, err);
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/* The negative cycle must be caught successfully */
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ASSERT_TRUE(c_BellmanFordSP_HasNegativeCycle(&sp));
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c_VertexIdList_t cycle_loop;
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c_VertexIdList_Init(&cycle_loop, 0, 0);
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err = c_BellmanFordSP_GetNegativeCycle(&sp, &cycle_loop);
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ASSERT_INT_EQ(C_SUCCESS, err);
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ASSERT_TRUE(c_VertexIdList_GetSize(&cycle_loop) > 0);
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c_VertexIdList_Destroy(&cycle_loop);
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c_BellmanFordSP_Destroy(&sp);
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c_EdgeWeightedDigraph_Destroy(&g);
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}
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int main(void) {
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TEST_START(BellmanFordSP_Engine_Suite);
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RUN_TEST(test_bellman_ford_shortest_path_negative_weights);
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RUN_TEST(test_bellman_ford_negative_cycle_detection);
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TEST_REPORT();
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RETURN_TEST_STATUS;
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}
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