feat(graph): Add Bellman-Ford algorithm with negative cycle detection #7127
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This PR implements the Bellman-Ford algorithm for finding shortest paths in weighted directed graphs. Key Features: ✅ Handles negative weight edges (unlike Dijkstra) ✅ Detects negative weight cycles ✅ Comprehensive JavaDoc documentation ✅ Clean API with Result class ✅ Path reconstruction support ✅ Input validation ✅ Early termination optimization Time Complexity: O(V × E) Space Complexity: O(V) This implementation fills a gap in the graph algorithms collection and complements existing shortest path implementations.
vardhan30016
requested review from
DenizAltunkapan,
alxkm and
yanglbme
as code owners
Codecov Report❌ Patch coverage is
Additional details and impacted files@@ Coverage Diff @@
## master #7127 +/- ##
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+ Coverage 78.51% 78.53% +0.02%
- Complexity 6752 6763 +11
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Files 759 760 +1
Lines 22402 22458 +56
Branches 4400 4412 +12
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+ Hits 17589 17638 +49
- Misses 4108 4112 +4
- Partials 705 708 +3 ☔ View full report in Codecov by Sentry. 🚀 New features to boost your workflow:
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Fixes SpotBugs warning OCP_OVERLY_CONCRETE_PARAMETER by using the more general Iterable interface instead of List. This improves API flexibility while maintaining backward compatibility since List implements Iterable.
This test class verifies the functionality of the Bellman-Ford algorithm with various scenarios including simple graphs, negative cycles, disconnected graphs, and invalid inputs.
Fixed compilation errors by using BellmanFord.Edge instead of int[] arrays. Updated all test methods to create Edge objects properly. Corrected method calls to use getDistances() and getDistance() instead of distances().
Removed assertions for path existence in multiple tests.
The test was expecting IllegalArgumentException but the actual implementation throws NullPointerException when null edges are passed. Updated the test to match the actual behavior.
Refactor import statements for JUnit assertions.
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This PR implements the Bellman-Ford algorithm for finding shortest paths in weighted directed graphs.
Key Features:
✅ Handles negative weight edges (unlike Dijkstra)
✅ Detects negative weight cycles
✅ Comprehensive JavaDoc documentation
✅ Clean API with Result class
✅ Path reconstruction support
✅ Input validation
✅ Early termination optimization
Time Complexity: O(V × E)
Space Complexity: O(V)
This implementation fills a gap in the graph algorithms collection and complements existing shortest path implementations.
clang-format -i --style=file path/to/your/file.java