def test_getitem(self):
l = range(11)
h = MaxHeap()
caught_exception = False
try:
print h[1]
except HeapEmptyError:
caught_exception = True
assert caught_exception == True
for i in l:
h.add(i)
caught_exception = False
try:
print h[-2]
except IndexError:
caught_exception = True
assert caught_exception == True
assert len(h) == 11
caught_exception = False
try:
print h[11]
except IndexError:
caught_exception = True
assert caught_exception == True
x = [10, 9, 5, 6, 8, 1, 4, 0, 3, 2, 7]
for i in xrange(11):
assert h[i] == x[i]
def test_remove(self):
l = [5, 4, 3, 2, 1, 6, 7, 8, 9, 0]
h = MaxHeap()
caught_exception = False
try:
assert h.peek() == None
except HeapEmptyError as e:
assert str(e) == "HeapEmptyError: 'peek(): Heap is empty'"
caught_exception = True
assert caught_exception == True
caught_exception = False
try:
assert h.remove() == None
except HeapEmptyError as e:
assert str(e) == "HeapEmptyError: 'remove(): Heap is empty'"
caught_exception = True
assert caught_exception == True
for i in xrange(len(l)):
h.add(l[i])
assert len(h) == 10
for i in xrange(9, -1, -1):
item = h.remove()
assert (len(h) == i)
assert item == i
def maxSlidingWindow(nums, k):
if not nums:
return []
h = MaxHeap()
for i in xrange(k):
h.add((nums[i], i))
max_list = [h.peek()[0]]
for i in xrange(1, len(nums) - k + 1):
# max is to the left of window
# remove all previous max items that are no longer in the window,
# from the heap
while h and h.peek()[1] < i:
h.remove()
# add item at end of current window, i+k-1, to the heap
h.add((nums[i + k - 1], i + k - 1))
# add current window's max from the top of the heap
max_list.append(h.peek()[0])
return max_list
def test_custom_comparator(self):
# Max heap using custom comparator making it a minheap
h = MaxHeap(lambda a, b: cmp(b, a))
for i in range(10):
h.add(i)
assert h.items == range(10)
for i in range(10):
assert h.remove() == i
def test_add(self):
l = [5, 4, 3, 2, 1, 6, 7, 8, 9, 0]
intermediate_heaps = [[5], [5, 4], [5, 4, 3], [5, 4, 3, 2],
[5, 4, 3, 2, 1], [6, 4, 5, 2, 1, 3],
[7, 4, 6, 2, 1, 3, 5], [8, 7, 6, 4, 1, 3, 5, 2],
[9, 8, 6, 7, 1, 3, 5, 2, 4],
[9, 8, 6, 7, 1, 3, 5, 2, 4, 0]]
h = MaxHeap()
for i in xrange(len(l)):
h.add(l[i])
assert h.items == intermediate_heaps[i]
def test_setitem(self):
l = [0, 1, 4, 2, 6, 5, 8, 3, 7, 9, 10]
h = MaxHeap()
for x in l:
h.add(x)
'''
10
/ \
9 6
/ \ / \
4 8 1 5
/ \ / \
0 3 2 7
'''
assert h.items == [10, 9, 6, 4, 8, 1, 5, 0, 3, 2, 7]
assert h[4] == 8
h[4] = 11 # calls MaxHeap's decreaseKey
'''
11
/ \
10 6
/ \ / \
4 9 1 5
/ \ / \
0 3 2 7
'''
assert h.items == [11, 10, 6, 4, 9, 1, 5, 0, 3, 2, 7]
assert h[0] == 11
h[0] = -1 # calls decreaseKey
'''
10
/ \
9 6
/ \ / \
4 7 1 5
/ \ / \
0 3 2 -1
'''
assert h.items == [10, 9, 6, 4, 7, 1, 5, 0, 3, 2, -1]
def test_increaseKey(self):
l = [0, 1, 4, 2, 6, 5, 8, 3, 7, 9, 10]
h = MaxHeap()
for x in l:
h.add(x)
'''
10
/ \
9 6
/ \ / \
4 8 1 5
/ \ / \
0 3 2 7
'''
assert h.items == [10, 9, 6, 4, 8, 1, 5, 0, 3, 2, 7]
caught_exception = False
try:
h.increaseKey(4, 5)
except ValueError as v:
assert v.message == "ValueError: increaseKey() - New key should be greater than current value"
caught_exception = True
assert caught_exception == True
h.increaseKey(4, 11)
'''
11
/ \
10 6
/ \ / \
4 9 1 5
/ \ / \
0 3 2 7
'''
assert h.items == [11, 10, 6, 4, 9, 1, 5, 0, 3, 2, 7]
def test_decreaseKey(self):
l = [0, 1, 4, 2, 6, 5, 8, 3, 7, 9, 10]
h = MaxHeap()
for x in l:
h.add(x)
'''
10
/ \
9 6
/ \ / \
4 8 1 5
/ \ / \
0 3 2 7
'''
assert h.items == [10, 9, 6, 4, 8, 1, 5, 0, 3, 2, 7]
caught_exception = False
try:
h.decreaseKey(4, 10)
except ValueError as v:
assert v.message == "ValueError: decreaseKey() - New key should be lesser than current value"
caught_exception = True
assert caught_exception == True
h.decreaseKey(0, -1)
'''
9
/ \
8 6
/ \ / \
4 7 1 5
/ \ / \
0 3 2 -1
'''
assert h.items == [9, 8, 6, 4, 7, 1, 5, 0, 3, 2, -1]
def test_custom_items(self):
class Record:
def __init__(self, a, b, c):
self.a = a
self.b = b
self.c = c
# by default, using 'b' as key to compare
def __cmp__(self, other):
return cmp(self.b, other.b)
def __str__(self):
return "(%s, %s, %s)" % (self.a, self.b, self.c)
h = MaxHeap()
h.add(Record("record1", 1, 100))
h.add(Record("record4", 5, 125))
h.add(Record("record3", 2, 50))
h.add(Record("record2", 3, 25))
h.add(Record("record5", 4, 5))
sorted_records_bs = []
h.sorted(lambda x, l: l.append(x.b), sorted_records_bs)
assert sorted_records_bs == range(5, 0, -1)
h2 = MaxHeap(lambda r1, r2: cmp(r1.a, r2.a))
h2.add(Record("record1", 1, 100))
h2.add(Record("record4", 5, 125))
h2.add(Record("record3", 2, 50))
h2.add(Record("record2", 3, 25))
h2.add(Record("record5", 4, 5))
sorted_records_as = []
h2.sorted(lambda x, l: l.append(x.a), sorted_records_as)
assert sorted_records_as == [
"record" + str(i) for i in xrange(5, 0, -1)
]
h3 = MaxHeap(lambda r1, r2: cmp(r1.c, r2.c))
h3.add(Record("record1", 1, 100))
h3.add(Record("record4", 5, 125))
h3.add(Record("record3", 2, 50))
h3.add(Record("record2", 3, 25))
h3.add(Record("record5", 4, 5))
sorted_records_cs = []
h3.sorted(lambda x, l: l.append(x.c), sorted_records_cs)
assert sorted_records_cs == sorted([100, 125, 50, 25, 5])[::-1]