diff options
Diffstat (limited to 'vendor/github.com/onsi/gomega/matchers/support/goraph/bipartitegraph/bipartitegraphmatching.go')
-rw-r--r-- | vendor/github.com/onsi/gomega/matchers/support/goraph/bipartitegraph/bipartitegraphmatching.go | 159 |
1 files changed, 159 insertions, 0 deletions
diff --git a/vendor/github.com/onsi/gomega/matchers/support/goraph/bipartitegraph/bipartitegraphmatching.go b/vendor/github.com/onsi/gomega/matchers/support/goraph/bipartitegraph/bipartitegraphmatching.go new file mode 100644 index 000000000..8181f43a4 --- /dev/null +++ b/vendor/github.com/onsi/gomega/matchers/support/goraph/bipartitegraph/bipartitegraphmatching.go @@ -0,0 +1,159 @@ +package bipartitegraph + +import . "github.com/onsi/gomega/matchers/support/goraph/node" +import . "github.com/onsi/gomega/matchers/support/goraph/edge" +import "github.com/onsi/gomega/matchers/support/goraph/util" + +func (bg *BipartiteGraph) LargestMatching() (matching EdgeSet) { + paths := bg.maximalDisjointSLAPCollection(matching) + + for len(paths) > 0 { + for _, path := range paths { + matching = matching.SymmetricDifference(path) + } + paths = bg.maximalDisjointSLAPCollection(matching) + } + + return +} + +func (bg *BipartiteGraph) maximalDisjointSLAPCollection(matching EdgeSet) (result []EdgeSet) { + guideLayers := bg.createSLAPGuideLayers(matching) + if len(guideLayers) == 0 { + return + } + + used := make(map[Node]bool) + + for _, u := range guideLayers[len(guideLayers)-1] { + slap, found := bg.findDisjointSLAP(u, matching, guideLayers, used) + if found { + for _, edge := range slap { + used[edge.Node1] = true + used[edge.Node2] = true + } + result = append(result, slap) + } + } + + return +} + +func (bg *BipartiteGraph) findDisjointSLAP( + start Node, + matching EdgeSet, + guideLayers []NodeOrderedSet, + used map[Node]bool, +) ([]Edge, bool) { + return bg.findDisjointSLAPHelper(start, EdgeSet{}, len(guideLayers)-1, matching, guideLayers, used) +} + +func (bg *BipartiteGraph) findDisjointSLAPHelper( + currentNode Node, + currentSLAP EdgeSet, + currentLevel int, + matching EdgeSet, + guideLayers []NodeOrderedSet, + used map[Node]bool, +) (EdgeSet, bool) { + used[currentNode] = true + + if currentLevel == 0 { + return currentSLAP, true + } + + for _, nextNode := range guideLayers[currentLevel-1] { + if used[nextNode] { + continue + } + + edge, found := bg.Edges.FindByNodes(currentNode, nextNode) + if !found { + continue + } + + if matching.Contains(edge) == util.Odd(currentLevel) { + continue + } + + currentSLAP = append(currentSLAP, edge) + slap, found := bg.findDisjointSLAPHelper(nextNode, currentSLAP, currentLevel-1, matching, guideLayers, used) + if found { + return slap, true + } + currentSLAP = currentSLAP[:len(currentSLAP)-1] + } + + used[currentNode] = false + return nil, false +} + +func (bg *BipartiteGraph) createSLAPGuideLayers(matching EdgeSet) (guideLayers []NodeOrderedSet) { + used := make(map[Node]bool) + currentLayer := NodeOrderedSet{} + + for _, node := range bg.Left { + if matching.Free(node) { + used[node] = true + currentLayer = append(currentLayer, node) + } + } + + if len(currentLayer) == 0 { + return []NodeOrderedSet{} + } + guideLayers = append(guideLayers, currentLayer) + + done := false + + for !done { + lastLayer := currentLayer + currentLayer = NodeOrderedSet{} + + if util.Odd(len(guideLayers)) { + for _, leftNode := range lastLayer { + for _, rightNode := range bg.Right { + if used[rightNode] { + continue + } + + edge, found := bg.Edges.FindByNodes(leftNode, rightNode) + if !found || matching.Contains(edge) { + continue + } + + currentLayer = append(currentLayer, rightNode) + used[rightNode] = true + + if matching.Free(rightNode) { + done = true + } + } + } + } else { + for _, rightNode := range lastLayer { + for _, leftNode := range bg.Left { + if used[leftNode] { + continue + } + + edge, found := bg.Edges.FindByNodes(leftNode, rightNode) + if !found || !matching.Contains(edge) { + continue + } + + currentLayer = append(currentLayer, leftNode) + used[leftNode] = true + } + } + + } + + if len(currentLayer) == 0 { + return []NodeOrderedSet{} + } + guideLayers = append(guideLayers, currentLayer) + } + + return +} |