forked from s425077/PotatoPlan
194 lines
4.0 KiB
C#
194 lines
4.0 KiB
C#
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using System;
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using System.Collections.Generic;
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using Microsoft.Xna.Framework;
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using System.Linq;
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using System.Text;
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using System.Threading.Tasks;
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class MinHeap
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{
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List<Nodes> arr = new List<Nodes>();
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public MinHeap()
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{
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arr = new List<Nodes>();
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}
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public void Insert(Nodes value)
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{
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arr.Add(value);
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siftUp(arr.Count - 1);
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}
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public void removeMin()
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{
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if (arr.Count == 0)
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{
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throw new Exception("Heap is empty!");
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}
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else
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{
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arr[0] = arr[arr.Count - 1];
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arr.RemoveAt(arr.Count - 1);
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if (arr.Count > 0)
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{
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siftDown(0);
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}
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}
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}
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private void siftUp(int index)
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{
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int parentIndex;
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Nodes temp;
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if (index != 0)
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{
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parentIndex = getParentIndex(index);
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if (arr[parentIndex].getF() > arr[index].getF())
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{
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temp = arr[parentIndex];
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arr[parentIndex] = arr[index];
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arr[index] = temp;
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siftUp(parentIndex);
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}
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}
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}
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private int getParentIndex(int index)
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{
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return (index - 1) / 2;
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}
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private void siftDown(int nodeIndex)
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{
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int leftChildIndex, rightChildIndex, minIndex;
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Nodes tmp;
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leftChildIndex = getLeftChildIndex(nodeIndex);
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rightChildIndex = getRightChildIndex(nodeIndex);
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if (rightChildIndex >= arr.Count)
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{
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if (leftChildIndex >= arr.Count)
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{
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return;
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}
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else
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{
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minIndex = leftChildIndex;
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}
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}
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else
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{
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if (arr[leftChildIndex].getF() <= arr[rightChildIndex].getF())
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{
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minIndex = leftChildIndex;
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}
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else
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{
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minIndex = rightChildIndex;
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}
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}
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if (arr[nodeIndex].getF() > arr[minIndex].getF())
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{
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tmp = arr[minIndex];
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arr[minIndex] = arr[nodeIndex];
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arr[nodeIndex] = tmp;
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siftDown(minIndex);
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}
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}
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private int getRightChildIndex(int nodeIndex)
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{
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return (2 * nodeIndex) + 2;
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}
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private int getLeftChildIndex(int nodeIndex)
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{
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return (2 * nodeIndex) + 1;
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}
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public Nodes getMin()
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{
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return arr[0];
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}
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public void BuildMinHeap(List<Nodes> input)
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{
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if (arr.Count > 0)
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{
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//clear the current heap
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for (int i = 0; i < arr.Count; i++)
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{
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arr[i] = input[i];
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}
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}
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for (int i = arr.Count - 1 / 2; i >= 0; i--)
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{
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MinHeapify(i);
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}
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}
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private void MinHeapify(int index)
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{
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int left = 2 * index;
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int right = (2 * index) + 1;
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int smallest = index;
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if (left < arr.Count && arr[left].getF() < arr[index].getF())
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{
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smallest = left;
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}
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else
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{
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smallest = index;
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}
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if (right < arr.Count && arr[right].getF() < arr[smallest].getF())
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{
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smallest = right;
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}
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if (smallest != index)
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{
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swap(ref arr, index, smallest);
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MinHeapify(smallest);
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}
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}
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private void swap(ref List<Nodes> input, int a, int b)
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{
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Nodes temp = input[a];
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input[a] = input[b];
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input[b] = temp;
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}
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public int GetSize()
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{
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return arr.Count;
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}
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public Boolean Exists(Vector2 coordinates)
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{
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if (arr.Count == 0)
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return false;
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foreach (Nodes node in arr)
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{
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if (node.getCords() == coordinates)
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return true;
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}
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return false;
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}
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public List<Nodes> GetList()
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{
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return arr;
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}
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public void deleteHeap()
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{
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arr.Clear();
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}
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}
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