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_build_heap(self):
l = range(10, -1, -1)
MaxHeap.build_heap(l)
assert l == range(10, -1, -1)
l = range(11)
MaxHeap.build_heap(l)
assert l == [10, 9, 6, 8, 4, 5, 2, 7, 3, 1, 0]
def test_after_single_push_delete_max_removes_the_value(self):
heap = MaxHeap()
heap.insert(0)
assert heap.size() == 1
assert not heap.is_empty()
heap.delete_max()
assert heap.size() == 0
assert heap.is_empty()
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_after_single_push_extract_max_removes_and_returns_value(self):
heap = MaxHeap()
heap.insert(0)
assert heap.size() == 1
assert not heap.is_empty()
assert heap.extract_max() == 0
assert heap.size() == 0
assert heap.is_empty()
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_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 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_sorted(self):
l = range(10, -1, -1)
MaxHeap.build_heap(l)
h = MaxHeap()
h.items = l
new_l = []
h.sorted(lambda i, l: l.append(i), new_l)
assert new_l == range(10, -1, -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_extract_max_of_empty_heap_raises_exception(self):
heap = MaxHeap()
with raises(MaxHeap.EmptyHeapException):
heap.extract_max()
def test_initialization(self):
heap = MaxHeap()
assert isinstance(heap, MaxHeap)
def test_isMaxHeap_i(self):
h = MaxHeap()
isHeap = h.isHeap_i
h.items = []
assert isHeap() == True
h.items = [1, 1]
assert isHeap() == True
h.items = [1, 1, 1]
assert isHeap() == True
'''
5
/ \
4 3
/ \
2 1
'''
h.items = [5, 4, 3, 2, 1]
assert isHeap() == True
'''
2
/
1
'''
h.items = [2, 1]
assert isHeap() == True
h.items = [1, 2]
assert isHeap() == False
'''
3
/ \
1 2
'''
h.items = [3, 1, 2]
assert isHeap() == True
'''
1
/ \
2 3
/ \
4 5
'''
h.items = [1, 2, 3, 4, 5]
assert isHeap() == False
h.items = range(10, -1, -1)
assert isHeap() == True
h.items = range(10)
assert isHeap() == False
def test_after_single_push_find_max_returns_value(self):
heap = MaxHeap()
heap.insert(0)
assert heap.find_max() == 0
def test_heap_size_is_3_after_three_pushes(self):
heap = MaxHeap()
heap.insert(0)
heap.insert(1)
heap.insert(2)
assert heap.size() == 3
def test_heap_size_is_1_after_single_push(self):
heap = MaxHeap()
heap.insert(0)
assert heap.size() == 1
def test_heap_is_not_empty_after_insert(self):
heap = MaxHeap()
heap.insert(0)
assert not heap.is_empty()
def test_empty_heap_is_empty(self):
heap = MaxHeap()
assert heap.is_empty()
def test_size_of_empty_heap_is_0(self):
heap = MaxHeap()
assert heap.size() == 0
def test_delete_max_of_empty_heap_raises_exception(self):
heap = MaxHeap()
with raises(MaxHeap.EmptyHeapException):
heap.delete_max()
def test_after_two_pushes_find_max_finds_larger_value(self):
heap = MaxHeap()
heap.insert(0)
heap.insert(1)
assert heap.find_max() == 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]
def test_sort(self):
assert MaxHeap.sort([1, 3, 5, 6, 4, 2]) == range(1, 7)
def test_two_pushes_and_two_extract_max_correct_values_empty_at_end(self):
heap = MaxHeap()
heap.insert(0)
heap.insert(1)
assert heap.size() == 2
assert not heap.is_empty()
assert heap.extract_max() == 1
assert heap.size() == 1
assert not heap.is_empty()
assert heap.extract_max() == 0
assert heap.size() == 0
assert heap.is_empty()
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
