mirror of
https://github.com/TheAlgorithms/Python.git
synced 2025-02-17 14:58:10 +00:00
implement max heap and more pythonic (#1685)
* implement max heap and more pythonic * add doctests for heap
This commit is contained in:
lanzhiwang
Christian Clauss
parent
d09a805804
commit
fc4c0f5bfd
|
|
@ -1,86 +1,134 @@
|
|||
#!/usr/bin/python
|
||||
#!/usr/bin/python3
|
||||
|
||||
# This heap class start from here.
|
||||
class Heap:
|
||||
def __init__(self): # Default constructor of heap class.
|
||||
|
||||
class Heap(object):
|
||||
"""
|
||||
>>> unsorted = [103, 9, 1, 7, 11, 15, 25, 201, 209, 107, 5]
|
||||
>>> h = Heap()
|
||||
>>> h.build_heap(unsorted)
|
||||
>>> h.display()
|
||||
[209, 201, 25, 103, 107, 15, 1, 9, 7, 11, 5]
|
||||
>>>
|
||||
>>> h.get_max()
|
||||
209
|
||||
>>> h.display()
|
||||
[201, 107, 25, 103, 11, 15, 1, 9, 7, 5]
|
||||
>>>
|
||||
>>> h.insert(100)
|
||||
>>> h.display()
|
||||
[201, 107, 25, 103, 100, 15, 1, 9, 7, 5, 11]
|
||||
>>>
|
||||
>>> h.heap_sort()
|
||||
>>> h.display()
|
||||
[1, 5, 7, 9, 11, 15, 25, 100, 103, 107, 201]
|
||||
>>>
|
||||
"""
|
||||
def __init__(self):
|
||||
self.h = []
|
||||
self.currsize = 0
|
||||
self.curr_size = 0
|
||||
|
||||
def leftChild(self, i):
|
||||
if 2 * i + 1 < self.currsize:
|
||||
return 2 * i + 1
|
||||
def get_left_child_index(self, i):
|
||||
left_child_index = 2 * i + 1
|
||||
if left_child_index < self.curr_size:
|
||||
return left_child_index
|
||||
return None
|
||||
|
||||
def rightChild(self, i):
|
||||
if 2 * i + 2 < self.currsize:
|
||||
return 2 * i + 2
|
||||
def get_right_child(self, i):
|
||||
right_child_index = 2 * i + 2
|
||||
if right_child_index < self.curr_size:
|
||||
return right_child_index
|
||||
return None
|
||||
|
||||
def maxHeapify(self, node):
|
||||
if node < self.currsize:
|
||||
m = node
|
||||
lc = self.leftChild(node)
|
||||
rc = self.rightChild(node)
|
||||
if lc is not None and self.h[lc] > self.h[m]:
|
||||
m = lc
|
||||
if rc is not None and self.h[rc] > self.h[m]:
|
||||
m = rc
|
||||
if m != node:
|
||||
temp = self.h[node]
|
||||
self.h[node] = self.h[m]
|
||||
self.h[m] = temp
|
||||
self.maxHeapify(m)
|
||||
def max_heapify(self, index):
|
||||
if index < self.curr_size:
|
||||
largest = index
|
||||
lc = self.get_left_child_index(index)
|
||||
rc = self.get_right_child(index)
|
||||
if lc is not None and self.h[lc] > self.h[largest]:
|
||||
largest = lc
|
||||
if rc is not None and self.h[rc] > self.h[largest]:
|
||||
largest = rc
|
||||
if largest != index:
|
||||
self.h[largest], self.h[index] = self.h[index], self.h[largest]
|
||||
self.max_heapify(largest)
|
||||
|
||||
def buildHeap(
|
||||
self, a
|
||||
): # This function is used to build the heap from the data container 'a'.
|
||||
self.currsize = len(a)
|
||||
self.h = list(a)
|
||||
for i in range(self.currsize // 2, -1, -1):
|
||||
self.maxHeapify(i)
|
||||
def build_heap(self, collection):
|
||||
self.curr_size = len(collection)
|
||||
self.h = list(collection)
|
||||
if self.curr_size <= 1:
|
||||
return
|
||||
for i in range(self.curr_size // 2 - 1, -1, -1):
|
||||
self.max_heapify(i)
|
||||
|
||||
def getMax(self): # This function is used to get maximum value from the heap.
|
||||
if self.currsize >= 1:
|
||||
def get_max(self):
|
||||
if self.curr_size >= 2:
|
||||
me = self.h[0]
|
||||
temp = self.h[0]
|
||||
self.h[0] = self.h[self.currsize - 1]
|
||||
self.h[self.currsize - 1] = temp
|
||||
self.currsize -= 1
|
||||
self.maxHeapify(0)
|
||||
self.h[0] = self.h.pop(-1)
|
||||
self.curr_size -= 1
|
||||
self.max_heapify(0)
|
||||
return me
|
||||
elif self.curr_size == 1:
|
||||
self.curr_size -= 1
|
||||
return self.h.pop(-1)
|
||||
return None
|
||||
|
||||
def heapSort(self): # This function is used to sort the heap.
|
||||
size = self.currsize
|
||||
while self.currsize - 1 >= 0:
|
||||
temp = self.h[0]
|
||||
self.h[0] = self.h[self.currsize - 1]
|
||||
self.h[self.currsize - 1] = temp
|
||||
self.currsize -= 1
|
||||
self.maxHeapify(0)
|
||||
self.currsize = size
|
||||
def heap_sort(self):
|
||||
size = self.curr_size
|
||||
for j in range(size - 1, 0, -1):
|
||||
self.h[0], self.h[j] = self.h[j], self.h[0]
|
||||
self.curr_size -= 1
|
||||
self.max_heapify(0)
|
||||
self.curr_size = size
|
||||
|
||||
def insert(self, data): # This function is used to insert data in the heap.
|
||||
def insert(self, data):
|
||||
self.h.append(data)
|
||||
curr = self.currsize
|
||||
self.currsize += 1
|
||||
while self.h[curr] > self.h[curr / 2]:
|
||||
temp = self.h[curr / 2]
|
||||
self.h[curr / 2] = self.h[curr]
|
||||
self.h[curr] = temp
|
||||
curr = curr / 2
|
||||
curr = (self.curr_size - 1) // 2
|
||||
self.curr_size += 1
|
||||
while curr >= 0:
|
||||
self.max_heapify(curr)
|
||||
curr = (curr - 1) // 2
|
||||
|
||||
def display(self): # This function is used to print the heap.
|
||||
def display(self):
|
||||
print(self.h)
|
||||
|
||||
|
||||
def main():
|
||||
l = list(map(int, input().split()))
|
||||
h = Heap()
|
||||
h.buildHeap(l)
|
||||
h.heapSort()
|
||||
h.display()
|
||||
for unsorted in [
|
||||
[],
|
||||
[0],
|
||||
[2],
|
||||
[3, 5],
|
||||
[5, 3],
|
||||
[5, 5],
|
||||
[0, 0, 0, 0],
|
||||
[1, 1, 1, 1],
|
||||
[2, 2, 3, 5],
|
||||
[0, 2, 2, 3, 5],
|
||||
[2, 5, 3, 0, 2, 3, 0, 3],
|
||||
[6, 1, 2, 7, 9, 3, 4, 5, 10, 8],
|
||||
[103, 9, 1, 7, 11, 15, 25, 201, 209, 107, 5],
|
||||
[-45, -2, -5]
|
||||
]:
|
||||
print('source unsorted list: %s' % unsorted)
|
||||
|
||||
h = Heap()
|
||||
h.build_heap(unsorted)
|
||||
print('after build heap: ', end=' ')
|
||||
h.display()
|
||||
|
||||
print('max value: %s' % h.get_max())
|
||||
print('delete max value: ', end=' ')
|
||||
h.display()
|
||||
|
||||
h.insert(100)
|
||||
print('after insert new value 100: ', end=' ')
|
||||
h.display()
|
||||
|
||||
h.heap_sort()
|
||||
print('heap sort: ', end=' ')
|
||||
h.display()
|
||||
print()
|
||||
|
||||
|
||||
if __name__ == "__main__":
|
||||
if __name__ == '__main__':
|
||||
main()
|
||||
|
|
|
|||
Loading…
Reference in New Issue
Block a user