105 lines
2.3 KiB
C#
105 lines
2.3 KiB
C#
#region Copyright & License Information
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/*
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* Copyright 2007-2011 The OpenRA Developers (see AUTHORS)
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* This file is part of OpenRA, which is free software. It is made
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* available to you under the terms of the GNU General Public License
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* as published by the Free Software Foundation. For more information,
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* see COPYING.
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*/
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#endregion
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using System;
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using System.Collections.Generic;
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namespace OpenRA.FileFormats
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{
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public class PriorityQueue<T>
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where T : IComparable<T>
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{
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List<T[]> items = new List<T[]>();
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int level, index;
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public PriorityQueue()
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{
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items.Add(new T[1]);
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}
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public void Add(T item)
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{
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int addLevel = level;
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int addIndex = index;
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while (addLevel >= 1 && Above(addLevel, addIndex).CompareTo(item) > 0)
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{
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items[addLevel][addIndex] = Above(addLevel, addIndex);
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--addLevel;
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addIndex >>= 1;
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}
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items[addLevel][addIndex] = item;
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if (++index >= (1 << level))
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{
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index = 0;
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if (items.Count <= ++level)
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items.Add(new T[1 << level]);
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}
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}
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public bool Empty { get { return (level == 0); } }
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T At(int level, int index) { return items[level][index]; }
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T Above(int level, int index) { return items[level - 1][index >> 1]; }
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T Last()
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{
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int lastLevel = level;
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int lastIndex = index;
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if (--lastIndex < 0)
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lastIndex = (1 << --lastLevel) - 1;
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return At(lastLevel, lastIndex);
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}
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public T Peek() { return At(0,0); }
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public T Pop()
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{
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if (level == 0 && index == 0)
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throw new InvalidOperationException("Attempting to pop empty PriorityQueue");
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T ret = At(0, 0);
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BubbleInto(0, 0, Last());
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if (--index < 0)
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index = (1 << --level) - 1;
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return ret;
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}
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void BubbleInto(int intoLevel, int intoIndex, T val)
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{
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int downLevel = intoLevel + 1;
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int downIndex = intoIndex << 1;
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if (downLevel > level || (downLevel == level && downIndex >= index))
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{
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items[intoLevel][intoIndex] = val;
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return;
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}
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if (downLevel <= level && downIndex < index - 1 &&
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At(downLevel, downIndex).CompareTo(At(downLevel, downIndex + 1)) >= 0)
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++downIndex;
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if (val.CompareTo(At(downLevel, downIndex)) <= 0)
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{
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items[intoLevel][intoIndex] = val;
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return;
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}
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items[intoLevel][intoIndex] = At(downLevel, downIndex);
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BubbleInto(downLevel, downIndex, val);
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}
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}
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}
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