def test_pull(full_heap, empty_heap):
full_heap.pop()
assert len(full_heap) == 11
assert helper(full_heap) is True
full_heap.pop()
assert len(full_heap) == 10
assert helper(full_heap) is True
empty_heap = BinHeap()
with pytest.raises(LookupError):
empty_heap.pop()
empty_heap.push(2)
assert empty_heap.pop() == 2
with pytest.raises(LookupError):
empty_heap.pop()
class PriorityQ(object):
"""Class for implementing a priority queue."""
def __init__(self):
self._heap = BinHeap(order='min')
self._cumulative_idx = 0
def insert(self, pri, val):
"""Insert a value at the end of the priority queue."""
self._heap.push((pri, self._cumulative_idx, val))
self._cumulative_idx += 1
def pop(self):
"""Remove and return the value at the root of the priority queue."""
try:
result = self._heap.pop()
return result[2]
except IndexError:
raise IndexError("Cannot pop from empty queue.")
def peek(self):
"""Return the value of at the root of the priority queue."""
try:
return self._heap._heap_list[0][2]
except IndexError:
return None
class PriorityQ(object):
"""Class for implementing a priority queue."""
def __init__(self):
self._heap = BinHeap(order='min')
self._cumulative_idx = 0
def insert(self, pri, val):
"""Insert a value at the end of the priority queue."""
self._heap.push((pri, self._cumulative_idx, val))
self._cumulative_idx += 1
def pop(self):
"""Remove and return the value at the root of the priority queue."""
try:
result = self._heap.pop()
return result[2]
except IndexError:
raise IndexError("Cannot pop from empty queue.")
def peek(self):
"""Return the value of at the root of the priority queue."""
try:
return self._heap._heap_list[0][2]
except IndexError:
return None
def test_pop_from_random_min_heap_in_sorted_order():
"""Test that popping all the items from a heap are in sorted order."""
from binheap import BinHeap
from random import randint
random_nums = [randint(0, 100) for _ in range(20)]
h = BinHeap(random_nums, is_max_heap=False)
popped = [h.pop() for _ in range(len(h._values) - 1)]
assert popped == sorted(random_nums)
def test_pop_from_unique_random_max_heap_in_sorted_order():
"""Test that popping all items from a unique heap are in sorted order."""
from binheap import BinHeap
from random import randint
random_nums = list(set([randint(0, 100) for _ in range(20)]))
h = BinHeap(random_nums)
popped = [h.pop() for _ in range(len(h._values) - 1)]
assert popped == sorted(random_nums, reverse=True)
def main():
# greeting
print("Welcome to Alice's Restaurant")
print("Open everyday except Thanksgiving.")
# display command list
print('Enter "a" to add a guest to the waiting list.')
print(
'Enter "s" to remove the next guest from the waiting list once they have been seated.'
)
print('Enter "q" to quit.')
# initialize reservation list & guest tracking number
reservationList = BinHeap()
guestnumber = 0
# get user imput
command = input("Command: ")
while command.lower() != "q":
# add guest
if command.lower() == "a":
name = input("Guest name: ")
priority = input("Guest priority: ")
guestnumber += 1
newguest = Guest(name, priority, guestnumber)
reservationList.insert(newguest)
print("A reservation for", newguest.name, "has been made.")
print("They have been assigned a priority of",
newguest.priority + ".")
print("They are currently", reservationList._heap.index(newguest),
"in line for a table.")
command = input("Command: ")
# get next guest from list
elif command.lower() == "s":
serving = reservationList.pop()
# check if there are guests on list
if serving:
print("Now serving", serving.name)
command = input("Command: ")
# warn if no guests on list
else:
print("There are no customers on the waiting list")
command = input("Command: ")
# control for invalid commands
elif command.lower() != "a" or "s":
print("Unrecognised command! Please try again.")
command = input("Command: ")
# exit program
else:
print("Goodbye!")
exit()
class Priorityq(object):
def __init__(self):
self.binheap = BinHeap()
self._count = 0
def insert(self, priority, val):
new_node = Node(priority, val, self._count)
self.binheap.push(new_node)
self._count += 1
def pop(self):
return_node = self.binheap.pop()
return return_node.val
def peek(self):
return self.binheap[0].val
def test_pop(iterable, expected):
from binheap import BinHeap
bh = BinHeap(iterable)
bh.pop()
assert bh._container == expected
def test_pop_empty_heap():
from binheap import BinHeap
bh = BinHeap()
with pytest.raises(IndexError):
bh.pop()
def create_path(s, end, grid,timelimit):
"Creates the shortest path between s (start) and end."
runtime = 0
# yay nested list comprehension
# the ons list is a 2d list of node status
# None means the node has not been checked yet
# a node object for a value means it is on the open list
# a False value means that it is on the closed list
ons = [[None for y in xrange(len(grid[x]))] for x in xrange(len(grid))]
#n is the current best node on the open list, starting with the initial node
n = node(s, None ,0, 0)
#we store the fscores of the nodes and the nodes themselves in a binary heap
openl = BinHeap()
#local functions accessed faster than global functions
get_time = time.clock
geth = get_h_score
while n.loc != end:
t = get_time()
#search adjacent nodes
#if the node is already on the open list, then
#and change their pointer the the current node
#if their path from current node is shorter than their
#previous path from previous parent
#if the node is not on the open list and is not a wall,
#add it to the open list
for x in xrange(n.loc[0] -1, n.loc[0] +2):
for y in xrange(n.loc[1] -1 , n.loc[1] + 2):
#the checked node can't be our central node
if (x,y) != n.loc:
#if the node is not on the closed list or open list
if ons[x][y] != None and ons[x][y] != False:
#get cost of the new path made from switching parents
new_cost = getdircost(n.loc,(x,y)) + n.gscore
# if the path from the current node is shorter
if new_cost < ons[x][y].gscore:
#find the index of the node
#to change in the open list
index = openl.index([ons[x][y].fscore,ons[x][y]])
#update the node to include this new change
openl[index][1] = node((x,y), n, new_cost,
geth((x,y),end) + new_cost)
#update the ons list and the fscore list in the heap
openl[index][0] = openl[index][1].fscore
ons[x][y] = openl[index][1]
#if the node is not a wall and not on the closed list
#then simply add it to the open list
elif grid[x][y] == True and ons[x][y] != False:
h = geth((x,y),end)
#movement score gets the direction cost
#added to the parent's directional cost
g = getdircost(n.loc,(x,y)) + n.gscore
ons[x][y] = node((x, y), n, g, g+h)#turn it on baby
openl.add([g+h, ons[x][y]])
#if the length of the open list is zero(all nodes on closed list)
#then return an empty path list
if len(openl) == 0:
print runtime
return []
#pop from the binary heap (the zeroth index stores fscore only)
#this will give the node with the smallest fscore, hopefully closer
#to the goal
n = openl.pop()[1]
#remove from the 'closed' list
ons[n.loc[0]][n.loc[1]] = False
runtime += get_time()-t
if runtime > timelimit:
print runtime
break
#Now we have our path, we just need to trace it
#trace the parent of every node until the beginning is reached
moves = []
while n.loc != s:
moves.insert(0,n.loc)
n = n.parent
print runtime
return moves
class PriorityQ(object):
"""Structure for values in a priorty queue.
Items added to the priority queue are given a priority. If not set
by the user, priority is set to be the lowest. When removing items,
higher priority items are removed before lower priority items.
"""
def __init__(self):
"""Construct a new priority queue."""
self._values = BinHeap()
self._min_priority = 0
def __len__(self):
"""Overwrite length to give us the amount of items in priority Q.
Get all the items from all the buckets in the priority Q.
"""
return sum(len(b) for b in self._all_values[1:])
@property
def _all_values(self):
return self._values._values
@property
def _size(self):
return self._values._size
def insert(self, val, priority=None):
"""Add a new value into the priority queue.
If no priority is given, uses current lowest priority.
"""
if priority is None:
priority = self._min_priority
if priority < self._min_priority:
self._min_priority = priority
try:
i = self._all_values.index(priority)
bucket = self._all_values[i]
bucket._values.enqueue(val)
except ValueError:
self._values.push(Bucket(priority, [val]))
def pop(self):
"""Remove the first value from priority Q.
If no values in bucket then bucket is removed.
"""
if len(self._all_values) < 2:
raise IndexError('Can not pop from empty priority Q.')
bucket = self._all_values[1]
result = bucket._values.dequeue()
if len(bucket._values) == 0:
self._values.pop()
return result
def peek(self):
"""Get the the most important item without removing it."""
if len(self._all_values) < 2:
return
bucket = self._all_values[1]
return bucket._values.peek()
def pop_empty():
heap = BinHeap()
with pytest.raises(IndexError):
heap.pop()
def test_pop_last():
heap = BinHeap()
heap.push(5)
assert heap.pop() == 5
assert heap.list == []
def test_pop_one_child():
heap = BinHeap()
heap.push(5)
heap.push(10)
assert heap.pop() == 5
