| | | 1 | | using System; |
| | | 2 | | using System.Collections.Generic; |
| | | 3 | | using System.Linq; |
| | | 4 | | using System.Text; |
| | | 5 | | using System.Threading.Tasks; |
| | | 6 | | |
| | | 7 | | namespace HeapLibrary |
| | | 8 | | { |
| | | 9 | | class HeapItem<T> |
| | | 10 | | { |
| | | 11 | | |
| | | 12 | | public int cost; |
| | | 13 | | public T obj; |
| | | 14 | | |
| | 2 | 15 | | public HeapItem(int cost, T o) |
| | 2 | 16 | | { |
| | 2 | 17 | | this.cost = cost; |
| | 2 | 18 | | this.obj = o; |
| | 2 | 19 | | } |
| | | 20 | | |
| | | 21 | | } |
| | | 22 | | |
| | | 23 | | public class Heap<T> |
| | | 24 | | { |
| | | 25 | | |
| | | 26 | | List<HeapItem<T>> heap = new List<HeapItem<T>>(); |
| | | 27 | | |
| | | 28 | | Dictionary<T, HeapItem<T>> items = new Dictionary<T, HeapItem<T>>(); |
| | | 29 | | |
| | | 30 | | public bool Contains(T o) |
| | | 31 | | { |
| | | 32 | | return items.ContainsKey(o); |
| | | 33 | | } |
| | | 34 | | |
| | | 35 | | public void Add(int cost, T o) |
| | | 36 | | { |
| | | 37 | | if (Contains(o)) |
| | | 38 | | { |
| | | 39 | | ChangeCost(cost, o); |
| | | 40 | | return; |
| | | 41 | | } |
| | | 42 | | |
| | | 43 | | HeapItem<T> item = new HeapItem<T>(cost, o); |
| | | 44 | | |
| | | 45 | | heap.Add(item); |
| | | 46 | | items.Add(o, item); |
| | | 47 | | |
| | | 48 | | MoveUp(heap.Count() - 1); |
| | | 49 | | } |
| | | 50 | | |
| | | 51 | | public void ChangeCost(int cost, T o) |
| | | 52 | | { |
| | | 53 | | for (int i = 0; i < heap.Count(); ++i) |
| | | 54 | | { |
| | | 55 | | HeapItem<T> item = heap[i]; |
| | | 56 | | if (ReferenceEquals(item.obj, o)) |
| | | 57 | | { |
| | | 58 | | if (item.cost == cost) return; |
| | | 59 | | if (item.cost > cost) |
| | | 60 | | { |
| | | 61 | | item.cost = cost; |
| | | 62 | | MoveDown(i); |
| | | 63 | | } |
| | | 64 | | else |
| | | 65 | | { |
| | | 66 | | item.cost = cost; |
| | | 67 | | MoveUp(i); |
| | | 68 | | } |
| | | 69 | | return; |
| | | 70 | | } |
| | | 71 | | } |
| | | 72 | | } |
| | | 73 | | |
| | | 74 | | public T Top() |
| | | 75 | | { |
| | | 76 | | if (heap.Count() == 0) return default(T); |
| | | 77 | | return heap[0].obj; |
| | | 78 | | } |
| | | 79 | | |
| | | 80 | | public T Pop() |
| | | 81 | | { |
| | | 82 | | if (heap.Count() == 0) return default(T); |
| | | 83 | | |
| | | 84 | | T first = Top(); |
| | | 85 | | items.Remove(first); |
| | | 86 | | |
| | | 87 | | if (heap.Count() == 1) |
| | | 88 | | { |
| | | 89 | | heap.RemoveAt(0); |
| | | 90 | | return first; |
| | | 91 | | } |
| | | 92 | | |
| | | 93 | | heap[0] = heap[heap.Count() - 1]; |
| | | 94 | | heap.RemoveAt(heap.Count() - 1); |
| | | 95 | | |
| | | 96 | | MoveDown(0); |
| | | 97 | | |
| | | 98 | | return first; |
| | | 99 | | } |
| | | 100 | | |
| | | 101 | | private void MoveUp(int index) |
| | | 102 | | { |
| | | 103 | | if (index == 0) return; |
| | | 104 | | HeapItem<T> i1 = heap[index]; |
| | | 105 | | HeapItem<T> i2 = heap[index / 2]; |
| | | 106 | | if (i1.cost < i2.cost) |
| | | 107 | | { |
| | | 108 | | heap[index / 2] = i1; |
| | | 109 | | heap[index] = i2; |
| | | 110 | | MoveUp(index / 2); |
| | | 111 | | } |
| | | 112 | | } |
| | | 113 | | |
| | | 114 | | private void MoveDown(int index) |
| | | 115 | | { |
| | | 116 | | if (index >= heap.Count()) return; |
| | | 117 | | HeapItem<T> i1 = heap[index]; |
| | | 118 | | |
| | | 119 | | HeapItem<T> i2 = (index * 2 < heap.Count() ? heap[index * 2] : null); |
| | | 120 | | HeapItem<T> i3 = (index * 2 + 1 < heap.Count() ? heap[index * 2 + 1] : null); |
| | | 121 | | |
| | | 122 | | if (i2 == null) |
| | | 123 | | { |
| | | 124 | | if (i3 == null) |
| | | 125 | | { |
| | | 126 | | return; |
| | | 127 | | } |
| | | 128 | | if (i1.cost > i3.cost) |
| | | 129 | | { |
| | | 130 | | heap[index] = i2; |
| | | 131 | | heap[index * 2 + 1] = i1; |
| | | 132 | | MoveDown(index * 2 + 1); |
| | | 133 | | } |
| | | 134 | | return; |
| | | 135 | | } |
| | | 136 | | |
| | | 137 | | if (i3 == null) |
| | | 138 | | { |
| | | 139 | | if (i1.cost > i2.cost) |
| | | 140 | | { |
| | | 141 | | heap[index] = i2; |
| | | 142 | | heap[index * 2] = i3; |
| | | 143 | | MoveDown(index * 2); |
| | | 144 | | } |
| | | 145 | | return; |
| | | 146 | | } |
| | | 147 | | |
| | | 148 | | if (i1.cost <= i2.cost && i1.cost <= i2.cost) |
| | | 149 | | { |
| | | 150 | | return; |
| | | 151 | | } |
| | | 152 | | |
| | | 153 | | if (i2.cost > i3.cost) |
| | | 154 | | { |
| | | 155 | | heap[index] = i3; |
| | | 156 | | heap[index * 2 + 1] = i1; |
| | | 157 | | MoveDown(index * 2 + 1); |
| | | 158 | | } |
| | | 159 | | else |
| | | 160 | | { |
| | | 161 | | heap[index] = i2; |
| | | 162 | | heap[index * 2 + 1] = i1; |
| | | 163 | | MoveDown(index * 2); |
| | | 164 | | } |
| | | 165 | | |
| | | 166 | | } |
| | | 167 | | |
| | | 168 | | } |
| | | 169 | | |
| | | 170 | | } |