using System;
using System.Collections.Generic;
using System.Collections;
using System.Text;
namespace MathGraph
{
/// <summary>
/// Loop of digraph
/// </summary>
public class DigraphLoop
{
/// <summary>
/// Paths in loop
/// </summary>
protected DigraphPath[] paths;
/// <summary>
/// Constructor
/// </summary>
/// <param name="paths">paths</param>
public DigraphLoop(DigraphPath[] paths)
{
if (paths.Length != 2)
{
throw new Exception("Illegal number of paths");
}
if ((paths[0].Source != paths[1].Source) | (paths[0].Target != paths[1].Target))
{
throw new Exception("Illegal endpoints of loop");
}
this.paths = paths;
}
/// <summary>
/// Overriden "Equals" function
/// </summary>
/// <param name="o">Object to compare</param>
/// <returns>True if o equals this object and false otherwise</returns>
public override bool Equals(object o)
{
DigraphLoop l = o as DigraphLoop;
return ((paths[0].Equals(l.paths[0]) & paths[1].Equals(l.paths[1]))
| (paths[0].Equals(l.paths[1]) & paths[1].Equals(l.paths[0])));
}
/// <summary>
/// Overriden "GetHashCode" function
/// </summary>
/// <returns>Hash code</returns>
public override int GetHashCode()
{
return paths[0].Count * paths[1].Count;
}
/// <summary>
/// Checks whether this loop contains the edge
/// </summary>
/// <param name="edge">The edge to check</param>
/// <returns>True if this loop contains edge and false otherwise</returns>
public bool Contains(DigraphEdge edge)
{
return paths[0].Contains(edge) | paths[1].Contains(edge);
}
/// <summary>
/// Checks whether this loop contains object
/// </summary>
/// <param name="o">The object to check</param>
/// <returns>True if this loop contains the object and false otherwise</returns>
public bool ContainsObject(object o)
{
return paths[0].ContainsObject(o) | paths[1].ContainsObject(o);
}
/// <summary>
/// Reducing
/// </summary>
public void Reduce()
{
reduceBegin();
reduceEnd();
}
/// <summary>
/// Return i - ths path
/// </summary>
public DigraphPath this[int i]
{
get
{
return paths[i];
}
}
/// <summary>
/// Reduces begin of loop
/// </summary>
protected void reduceBegin()
{
int i = 0;
for (; i < paths[0].Count & i < paths[1].Count; i++)
{
if (paths[0][i] != paths[1][i])
{
break;
}
}
for (int j = 0; j < 2; j++)
{
DigraphPath path = paths[j];
ArrayList l = new ArrayList();
for (int k = i; k < path.Count; k++)
{
l.Add(path[k]);
}
paths[j] = new DigraphPath(l, false);
}
}
/// <summary>
/// Reduces end of loop
/// </summary>
protected void reduceEnd()
{
int i = 1;
for (; i < paths[0].Count & i < paths[1].Count; i++)
{
if (paths[0][paths[0].Count - i] != paths[1][paths[1].Count - i])
{
break;
}
}
for (int j = 0; j < 2; j++)
{
DigraphPath path = paths[j];
ArrayList l = new ArrayList();
for (int k = 0; k < path.Count - i + 1; k++)
{
l.Add(path[k]);
}
paths[j] = new DigraphPath(l, false);
}
}
}
}
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