def testHeapify(self):
size = 100
array = [random.randrange(size) for i in range(size)]
copy = sorted(array)
heapify(array)
self.checkHeapProperty(array)
for elem in copy:
self.assertEqual(heappop(array), elem)
def get_shortest_path(start, end, vlist):
# distances使用字典的方式保存每一个顶点到start点的距离
distances = {}
# 从start到某点的最优路径的前一个结点
# eg:start->B->D->E,则previous[E]=D,previous[D]=B,等等
previous = {}
# 用来保存图中所有顶点的到start点的距离的优先队列
# 这个距离不一定是最短距离
nodes = []
for vertex in vlist:
if vertex == start:
distances[vertex] = 0 # 将start点的距离初始化为0
heap.heappush(nodes, [0, vertex])
# nodes.append([0,vertex])
elif vertex in g.neighboringVertices(start):
distances[vertex] = length(start, vertex) # 把与star点相连的结点距离start点的距离初始化为对应的道路长度
heap.heappush(nodes, [length(start, vertex), vertex])
# nodes.append([length(start, vertex), vertex])
previous[vertex] = start
else:
distances[vertex] = 9999 # 把与start点不直接连接的结点距离start的距离初始化为9999
heap.heappush(nodes, [9999, vertex])
# nodes.append([9999, vertex])
previous[vertex] = None
shortest_path = [1]
lenPath = 0
while nodes:
smallest = heap.heappop(nodes)[1] # 取出队列中最小距离的结点
# smallest = nodes.pop()[1]
if smallest == end:
shortest_path = []
lenPath = distances[smallest]
temp = smallest
#print('previous[temp]:',temp)
while (temp != start) :
shortest_path.append(temp)
temp = previous[temp]
shortest_path.append(temp) # 将start点也加入到shortest_path中
if distances[smallest] == 9999:
# 所有点不可达
break
# 遍历与smallest相连的结点，更新其与结点的距离、前继节点
for neighbor in g.neighboringVertices(smallest):
dis = distances[smallest] + length(smallest, neighbor.getLabel())
if dis < distances[neighbor.getLabel()]:
distances[neighbor.getLabel()] = dis
previous[neighbor.getLabel()] = smallest # 更新与smallest相连的结点的前继节点
for node in nodes:
if node[1] == neighbor.getLabel():
node[0] = dis # 更新与smallest相连的结点到start的距离
break
heap.heapify(nodes)
return shortest_path, lenPath
def testHeappush(self):
size = 100
array = [random.randrange(size) for i in range(size)]
copy = sorted(array)
heap = []
for elem in array:
heappush(heap, elem)
self.checkHeapProperty(heap)
for elem in copy:
self.assertEqual(heappop(heap), elem)
def maxGasStationDistance(stations, K):
distances = []
n = len(stations)
for i in range(n-1):
d = stations[i+1] - stations[i]
heappush(distances, [-d, 1, d])
for j in range(K):
item = heappop(distances)
prio, num, curr = item
num += 1
heappush(distances, [-(curr/num), num, curr])
return -distances[0][0]
def get_shortest_path(start, end, vlist):
distances = {}
previous = {}
nodes = []
for vertex in vlist:
if vertex == start:
distances[vertex] = 0
heap.heappush(nodes, [0, vertex])
elif vertex in h.neighboringVertices(start):
distances[vertex] = length2(start, vertex)
heap.heappush(nodes, [length2(start, vertex), vertex])
previous[vertex] = start
else:
distances[vertex] = inf
heap.heappush(nodes, [inf, vertex])
previous[vertex] = None
shortest_path = [1]
lenPath = 0
while nodes:
smallest = heap.heappop(nodes)[1]
# smallest = nodes.pop()[1]
if smallest == end:
shortest_path = []
lenPath = distances[smallest]
temp = smallest
while (temp != start):
shortest_path.append(temp)
temp = previous[temp]
shortest_path.append(temp)
if distances[smallest] == inf:
break
for neighbor in h.neighboringVertices(smallest):
dis = distances[smallest] + length2(smallest, neighbor.getLabel())
if dis < distances[neighbor.getLabel()]:
distances[neighbor.getLabel()] = dis
previous[neighbor.getLabel()] = smallest
for node in nodes:
if node[1] == neighbor.getLabel():
node[0] = dis
break
heap.heapify(nodes)
return shortest_path, lenPath
def rankASs(distances, min_transcripts=3):
from heap import heap, heappop # @UnresolvedImport
distance_list = []
contig_list = []
for transcript in distances.keys():
contigs = list(distances[transcript].keys())
if len(contigs) >= min_transcripts:
for i in range(len(contigs)):
sum_dist = 0
for j in range(len(contigs)):
if i != j:
sum_dist += distances[transcript][contigs[i]][
contigs[j]]
contig_list.append(transcript + '_' + contigs[i])
distance_list.append(sum_dist / (len(contigs) - 1))
heap_distances, heap_contigs = heap(distance_list, contig_list)
return heappop(heap_distances, heap_contigs)
def sortGraph(graph):
indegree = {node: 0 for node in graph}
for c in graph:
for neighbor in graph[c]:
indegree[neighbor] += 1
q = [node for node in graph if indegree[node] == 0]
heapify(q)
tpOrder = ''
while q:
cur = heappop(q)
tpOrder = tpOrder + cur
for nc in graph[cur]:
indegree[nc] = indegree[nc] - 1
if indegree[nc] == 0:
heappush(tpOrder, nc)
if len(tpOrder) == len(graph):
return True
return False
class Find_Near():
def __init__(self):
self.point_list = []
def add_point(self, Point):
self.point_list.append(Point)
def find_nearest(self, center, p):
if len(self.point_list) < p:
raise 'Not enough points stored'
elif len(self.point_list) == p:
return self.point_list
heap = []
for point in self.point_list:
distance = self.calculate_distance(point, center)
heappush(heap, (distance, point))
distance , point
nearest = []
for i in range(p):
nearest.append(heappop(heap)[1])
return nearrest