def default_partition(arr: List[C], begin: int, end: int) -> int:
pivot = arr[end]
i = begin
for j in range(begin, end):
if arr[j] <= pivot:
swap(arr, i, j)
i += 1
swap(arr, i, end)
return i
def _percolate_up(self) -> None:
if not self.storage:
return
i = self.size - 1
while i > 0:
parent = i // 2
if self.storage[parent] < self.storage[i]:
swap(self.storage, parent, i)
else:
break
i = parent
def sift_down(self, i=0) -> None:
# Cormen 6.2-2
last_index = self.size - 1
while True:
left_child = 2 * i + 1
right_child = 2 * i + 2
if left_child > last_index:
return
smallest = (left_child if right_child > last_index
or self.storage[left_child] < self.storage[right_child]
else right_child)
if self.storage[i] > self.storage[smallest]:
swap(self.storage, i, smallest)
i = smallest
def random_partition(arr: List[C], begin: int, end: int) -> int:
pivot = randint(begin, end)
swap(arr, pivot, end)
return default_partition(arr, begin, end)