151 lines
3.4 KiB
C#
151 lines
3.4 KiB
C#
/*
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Bullet for XNA Copyright (c) 2003-2007 Vsevolod Klementjev http://www.codeplex.com/xnadevru
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Bullet original C++ version Copyright (c) 2003-2007 Erwin Coumans http://bulletphysics.com
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This software is provided 'as-is', without any express or implied
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warranty. In no event will the authors be held liable for any damages
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arising from the use of this software.
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Permission is granted to anyone to use this software for any purpose,
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including commercial applications, and to alter it and redistribute it
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freely, subject to the following restrictions:
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1. The origin of this software must not be misrepresented; you must not
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claim that you wrote the original software. If you use this software
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in a product, an acknowledgment in the product documentation would be
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appreciated but is not required.
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2. Altered source versions must be plainly marked as such, and must not be
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misrepresented as being the original software.
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3. This notice may not be removed or altered from any source distribution.
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*/
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using System;
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using System.Collections.Generic;
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using System.Text;
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namespace XnaDevRu.BulletX
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{
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public class UnionFind : IDisposable
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{
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private List<Element> _elements = new List<Element>();
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public int ElementCount
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{
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get { return _elements.Count; }
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}
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public void SortIslands()
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{
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for (int i = 0; i < _elements.Count; i++)
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{
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_elements[i].ID = Find(i);
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_elements[i].Size = i;
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}
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_elements.Sort(Sort);
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}
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private static int Sort(Element x, Element y)
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{
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if (x.ID < y.ID) return -1;
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//else if (x.ID > y.ID) return 1;
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else return 0;
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}
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public void Reset(int number)
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{
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Allocate(number);
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for (int i = 0; i < number; i++)
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{
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Element element = new Element();
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element.ID = i;
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element.Size = 1;
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_elements.Insert(i, element);
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}
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}
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public bool IsRoot(int index)
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{
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return (_elements[index].Size == index);
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}
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public Element this[int index]
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{
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get { return _elements[index]; }
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}
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public void Allocate(int number)
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{
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//Does nothing
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_elements = new List<Element>(number);
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}
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public bool Find(int i, int j)
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{
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return (Find(i) == Find(j));
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}
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public int Find(int i)
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{
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while (i != _elements[i].ID)
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{
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//Element element = _elements[i];
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//element.ID = _elements[_elements[i].ID].ID;
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_elements[i].ID = _elements[_elements[i].ID].ID;
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i = _elements[i].ID;
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}
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return i;
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}
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public void Unite(int p, int q)
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{
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int i = Find(p), j = Find(q);
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if (i == j)
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return;
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//weighted quick union, this keeps the 'trees' balanced, and keeps performance of unite O( log(n) )
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//if (_elements[i].Size < _elements[j].Size)
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//{
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// Element element = _elements[i];
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// element.ID = j;
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// _elements[i] = element;
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// element = _elements[j];
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// element.Size += _elements[i].Size;
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// _elements[j] = element;
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//}
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//else
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//{
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// Element element = _elements[j];
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// element.ID = i;
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// _elements[j] = element;
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// element = _elements[i];
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// element.Size += _elements[j].Size;
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// _elements[i] = element;
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//}
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_elements[i].ID = j;
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_elements[j].Size += _elements[i].Size;
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}
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#region IDisposable Members
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public void Dispose()
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{
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_elements.Clear();
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}
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#endregion
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}
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public class Element
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{
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private int _id;
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private int _size;
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public int ID { get { return _id; } set { _id = value; } }
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public int Size { get { return _size; } set { _size = value; } }
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}
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} |