class MinPQ: def __init__(self,items = None): self._minHeap = MinHeap() self.count = 0 if isinstance(items,collections.Iterable): #if items have been supplied build a MinPQ from those items. for elm in items: self.enqueue(elm) def __iter__(self): return self def next(self): if not self.isEmpty(): return self.dequeue() else: raise StopIteration() def enqueue(self,n): self._minHeap.append(n) self.count += 1 def dequeue(self): j = self._minHeap.delMin() self.count -= 1 return j def isEmpty(self): return self.count == 0 def show(self): print(self._minHeap)
def __init__(self,items = None): self._minHeap = MinHeap() self.count = 0 if isinstance(items,collections.Iterable): #if items have been supplied build a MinPQ from those items. for elm in items: self.enqueue(elm)
def nearestNeighbor(trainingSet, testRow, classCol, k):
minHeap = MinHeap(len(trainingSet.index))
for row in trainingSet.iterrows():
dropRow = row[1].drop(classCol)
dist = findDistance(dropRow, testRow, classCol)
minHeap.insert((row, dist))
minHeap.minHeap()
# Determine class by k neighbor voting
votes = {}
for i in range(k):
minVal = minHeap.remove()
if minVal[0][1][classCol] in votes:
votes[minVal[0][1][classCol]] += 1
else:
votes[minVal[0][1][classCol]] = 1
maxVotes = 0
predictedClass = ""
for key in votes:
if votes[key] > maxVotes:
maxVotes = votes[key]
predictedClass = key
return 0 if (predictedClass == testRow[1][classCol]) else 1
def ksort(inputlist, k ):
indx =1
heap = MinHeap()
res = []
heap.insertKey(inputlist[0])
while len(heap.heap)>0:
for i in range(k+1):
if indx < len(inputlist):
heap.insertKey(inputlist[indx])
indx+=1
minValue = heap.extractMin()
res.append(minValue)
return res
def huffman_tree(self, frequencyMap):
#--------------------------------------------
#build a priority queue - a min Heap of all characters and their frequencies, the min heap will sort the data
minh = MinHeap(self.priorityCallback)
for char, freq in frequencyMap.items():
minh.push(Node(char, freq))
#--------------------------------------------
#Merge sets of nodes in heap to create a huffman tree, Repeat until only one node remains in the priority queue.
while (minh.size() > 1):
#extract two minimum frequency node from min heap
node1 = minh.pop()
node2 = minh.pop()
"""
Create a new internal node with a frequency equal to the sum of the two nodes frequencies. Set the first extracted node as its left child and the other extracted node as its right child. Add this node to the min heap.
"""
#create newNode
newNode = Node()
#set frequency equal to the sum of the two nodes frequencies
nPriority = (node1.get_priority() if node1 else
0) + (node2.get_priority() if node2 else 0)
if (nPriority > 0):
newNode.set_priority(nPriority)
#Set the first extracted node as the left child
newNode.set_left_child(node1)
#Set the other extracted node as the right child
newNode.set_right_child(node2)
#add newNode to the min heap.
minh.push(newNode)
return minh
def Dijkstra(graph, start):# pylint: disable=invalid-name
""" Main implementation using Priority Queue"""
priorityqueue = MinHeap()
priorityqueue.insertKey(start)
distance = [-1 for i in range(graph.num_of_nodes)]
path = [-1 for i in range(graph.num_of_nodes)]
while not priorityqueue.empty():
v = priorityqueue.extractMin() # pylint: disable=invalid-name
print(graph.graph.items(),"...",v)
for adj, weight in graph.graph.get(v):
d = distance[v] + weight # pylint: disable=invalid-name
if distance[adj] == -1:
distance[adj] = d
priorityqueue.insertKey(adj)
priorityqueue.decreaseKey(adj, d)
elif distance[adj] > d:
distance[adj] = d
priorityqueue.decreaseKey(adj, d)
path[adj] = v
return distance, path
def test_add_AddsElemToHeap(self):
minHeap = MinHeap()
minHeap.add(3)
firstItem = minHeap.heap[0]
self.assertEqual(firstItem, 3)
def test_convertArrayToHeap_MaintainsHeapOrder(self):
minHeap = MinHeap()
arr = [3, 9, 12, 7, 1]
expectedHeap = [1, 3, 12, 9, 7]
res = minHeap.convertArrayToHeap(arr)
self.assertListEqual(expectedHeap, res)
def dijkstraFindPath(self,
startPoint,
endPoint,
pointsInPath,
checkLineIntersection=False,
searchRange=DEFAULT_SEARCH_RANGE):
# pre-calculate distances in a search range cube
self.gridScanDistances = []
for k in range(-searchRange, searchRange + 1):
grid2dDistances = []
for i in range(-searchRange, searchRange + 1):
tmp = []
for j in range(-searchRange, searchRange + 1):
tmp.append((i**2 + (j * LENGTH / WIDTH)**2 +
(k * LENGTH / HEIGHT)**2)**0.5)
grid2dDistances.append(tmp)
self.gridScanDistances.append(grid2dDistances)
self.grid[startPoint[2]][startPoint[1]][startPoint[0]].setDistance(0)
pq = MinHeap()
pq.insert(
self.grid[startPoint[2]][startPoint[1]][startPoint[0]], self.grid[
startPoint[2]][startPoint[1]][startPoint[0]].getDistance())
count = 0
while pq.counter != 0:
currGridPoint = pq.del_min()
if currGridPoint.getDistance(
) > LARGE_DISTANCE: # these are the points that cannot be reached from the start point
print("points covered: " + str(count))
print("Destination point cannot be reached")
raise Exception()
break
currGridPoint.visit()
currX = currGridPoint.x
currY = currGridPoint.y
currZ = currGridPoint.z
if (
currX, currY
) == endPoint: # if we've reached the endpoint, then its okay to stop
break
# go through all the neighbours of the current point
for k in range(-searchRange, searchRange + 1):
z = k + currZ
for i in range(-searchRange, searchRange + 1):
y = i + currY
for j in range(-searchRange, searchRange + 1):
x = j + currX
if x < 0 or x >= WIDTH or y < 0 or y >= LENGTH or z < 0 or z >= HEIGHT: # check if out of bounds
continue
# check if point has been visited and whether it is accessible or not
currPoint = self.grid[z][y][x]
if currPoint.beenVisited(
) or not currPoint.isAccessible():
continue
if checkLineIntersection: # option that adds a shitton of time to the algo
line = LineString([[currX, currY], [x, y]])
continueFlag = False
for noFlyZone in self.noFlyZones:
if line.intersects(noFlyZone):
continueFlag = True
break
if continueFlag:
continue
oldDist = currPoint.getDistance()
newDist = currGridPoint.getDistance(
) + self.gridScanDistances[k + searchRange][
i + searchRange][j + searchRange]
if newDist < oldDist:
currPoint.setDistance(newDist)
pq.insert(currPoint, currPoint.getDistance())
currPoint.setParent(currGridPoint)
count = count + 1
# check if the endpoint has actually been visited (probs not necessary but why not)
endGridPoint = self.grid[endPoint[2]][endPoint[1]][endPoint[0]]
if endGridPoint.getDistance() > LARGE_DISTANCE:
print("no path could be found")
raise Exception()
return
# now find the shortest path by going up the tree
startGridPoint = self.grid[startPoint[2]][startPoint[1]][startPoint[0]]
tempPath = []
while endGridPoint != startGridPoint:
if endGridPoint == None:
print("no path could be found between following two points: ",
end="")
print(startPoint, end="")
print(endPoint)
raise Exception()
return
tempPath.append((endGridPoint.x, endGridPoint.y, endGridPoint.z))
endGridPoint = endGridPoint.getParent()
tempPath.append((startGridPoint.x, startGridPoint.y, endGridPoint.z))
totalDistance = 0
# reverse them, append onto list then calculate distance
for x in range(len(tempPath) - 2, -1, -1):
totalDistance = totalDistance + (
abs(tempPath[x + 1][0] - tempPath[x][0])**2 +
abs(tempPath[x + 1][1] - tempPath[x][1])**2 +
abs(tempPath[x + 1][2] - tempPath[x][2])**2)**0.5
pointsInPath.append(tempPath[x])
self.gridReset()
return totalDistance
# Add, edit, or remove tests in this file.
# Treat it as your playground!
from minHeap import MinHeap
import unittest
test1 = MinHeap([2, 3, 1])
test2 = MinHeap([1, 2, 3, 4, 5, 6, 7, 8, 9])
test3 = MinHeap([48, 12, 24, 7, 8, -5, 24, 391, 24, 56, 2, 6, 8, 41])
test3.insert(76)
test3.remove()
test3.remove()
test3.insert(87)
test3a = MinHeap([[1, 48], [1, 12], [1, 24], [1, 7], [1, 8], [1, -5], [1, 24],
[1, 39], [1, 24], [1, 56], [1, 2], [1, 6], [1, 8], [1, 41]])
test3a.insert([1, 76])
test3a.remove()
test3a.remove()
test3a.insert([1, 9])
test3a.insert([1, 10])
test3a.insert([1, 87])
test3a.insert([1, -87])
test3a.insert([1, 49])
test4 = MinHeap(
[-4, 5, 10, 8, -10, -6, -4, -2, -5, 3, 5, -4, -5, -1, 1, 6, -7, -6, -7, 8])
test5 = MinHeap(
#!/user/bin/env python from minHeap import MinHeap mHeap = MinHeap() a = [3, 5, 6, 63, 47, 2, 46, 7] print(a) mHeap.min_heapify(a) b = mHeap.heap_sort() print(b) maxHeap = MinHeap() c = [23, 123, 422, 112, 42, 12, 23] d = [x * -1 for x in c] maxHeap.min_heapify(d) e = [x * -1 for x in maxHeap.heap_sort()] print(e)
def Dijkstra(graph, start): # pylint: disable=invalid-name
""" Main implementation using Priority Queue"""
priorityqueue = MinHeap()
priorityqueue.insertKey(start)
distance = [-1 for i in range(graph.num_of_nodes)]
path = [-1 for i in range(graph.num_of_nodes)]
while not priorityqueue.empty():
v = priorityqueue.extractMin() # pylint: disable=invalid-name
print(graph.graph.items(), "...", v)
for adj, weight in graph.graph.get(v):
d = distance[v] + weight # pylint: disable=invalid-name
if distance[adj] == -1:
distance[adj] = d
priorityqueue.insertKey(adj)
priorityqueue.decreaseKey(adj, d)
elif distance[adj] > d:
distance[adj] = d
priorityqueue.decreaseKey(adj, d)
path[adj] = v
return distance, path
