Package org.jgrapht.alg.cycle
Class SzwarcfiterLauerSimpleCycles<V,E>
- java.lang.Object
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- org.jgrapht.alg.cycle.SzwarcfiterLauerSimpleCycles<V,E>
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- Type Parameters:
V
- the vertex type.E
- the edge type.
- All Implemented Interfaces:
DirectedSimpleCycles<V,E>
public class SzwarcfiterLauerSimpleCycles<V,E> extends java.lang.Object implements DirectedSimpleCycles<V,E>
Find all simple cycles of a directed graph using the Schwarcfiter and Lauer's algorithm.See:
J.L.Szwarcfiter and P.E.Lauer, Finding the elementary cycles of a directed graph in O(n + m) per cycle, Technical Report Series, #60, May 1974, Univ. of Newcastle upon Tyne, Newcastle upon Tyne, England.
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Field Summary
Fields Modifier and Type Field Description private java.util.Map<V,java.util.Set<V>>
bSets
private java.util.List<java.util.List<V>>
cycles
private DirectedGraph<V,E>
graph
private V[]
iToV
private java.util.Set<V>
marked
private int[]
position
private boolean[]
reach
private java.util.Map<V,java.util.Set<V>>
removed
private java.util.ArrayDeque<V>
stack
private java.util.List<V>
startVertices
private java.util.Map<V,java.lang.Integer>
vToI
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Constructor Summary
Constructors Constructor Description SzwarcfiterLauerSimpleCycles()
Create a simple cycle finder with an unspecified graph.SzwarcfiterLauerSimpleCycles(DirectedGraph<V,E> graph)
Create a simple cycle finder for the specified graph.
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Method Summary
All Methods Instance Methods Concrete Methods Modifier and Type Method Description private void
clearState()
private boolean
cycle(int v, int q)
java.util.List<java.util.List<V>>
findSimpleCycles()
Finds the simple cycles of the graph.
Note that the full algorithm is executed on every call since the graph may have changed between calls.private java.util.Set<V>
getBSet(V v)
DirectedGraph<V,E>
getGraph()
Returns the graph on which the simple cycle search algorithm is executed by this object.private java.util.Set<V>
getRemoved(V v)
private void
initState()
private void
noCycle(int x, int y)
void
setGraph(DirectedGraph<V,E> graph)
Sets the graph on which the simple cycle search algorithm is executed by this object.private java.lang.Integer
toI(V v)
private V
toV(int i)
private void
unmark(int x)
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Field Detail
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graph
private DirectedGraph<V,E> graph
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cycles
private java.util.List<java.util.List<V>> cycles
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iToV
private V[] iToV
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vToI
private java.util.Map<V,java.lang.Integer> vToI
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stack
private java.util.ArrayDeque<V> stack
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marked
private java.util.Set<V> marked
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position
private int[] position
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reach
private boolean[] reach
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startVertices
private java.util.List<V> startVertices
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Constructor Detail
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SzwarcfiterLauerSimpleCycles
public SzwarcfiterLauerSimpleCycles()
Create a simple cycle finder with an unspecified graph.
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SzwarcfiterLauerSimpleCycles
public SzwarcfiterLauerSimpleCycles(DirectedGraph<V,E> graph)
Create a simple cycle finder for the specified graph.- Parameters:
graph
- - the DirectedGraph in which to find cycles.- Throws:
java.lang.IllegalArgumentException
- if the graph argument isnull
.
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Method Detail
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getGraph
public DirectedGraph<V,E> getGraph()
Returns the graph on which the simple cycle search algorithm is executed by this object.- Specified by:
getGraph
in interfaceDirectedSimpleCycles<V,E>
- Returns:
- The graph.
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setGraph
public void setGraph(DirectedGraph<V,E> graph)
Sets the graph on which the simple cycle search algorithm is executed by this object.- Specified by:
setGraph
in interfaceDirectedSimpleCycles<V,E>
- Parameters:
graph
- the graph.
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findSimpleCycles
public java.util.List<java.util.List<V>> findSimpleCycles()
Finds the simple cycles of the graph.
Note that the full algorithm is executed on every call since the graph may have changed between calls.- Specified by:
findSimpleCycles
in interfaceDirectedSimpleCycles<V,E>
- Returns:
- The list of all simple cycles. Possibly empty but never
null
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cycle
private boolean cycle(int v, int q)
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noCycle
private void noCycle(int x, int y)
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unmark
private void unmark(int x)
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initState
private void initState()
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clearState
private void clearState()
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toI
private java.lang.Integer toI(V v)
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toV
private V toV(int i)
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