class ArrayQueue(Queuebase):
"""数组队列"""
def __init__(self, capacity=10):
self._array = Array(capacity)
def enqueue(self, e):
"""入队"""
self._array.add_Last(e)
def dequeue(self):
"""出队"""
return self._array.remove_First()
def get_Front(self):
"""获得队首元素"""
return self._array.get_First()
def get_Size(self):
"""获得队列内元素数量"""
return self._array.get_Size()
def is_Empty(self):
"""查看队列是否为空"""
return self._array.is_Empty()
def get_Capacity(self):
"""查看队列的容量"""
return self._array.get_Capacity()
def __str__(self):
StringList = []
StringList.append("Queue:size = %s, capacity = %d \n" %
(self.get_Size(), self.get_Capacity()))
StringList.append('front [')
for i in range(self.get_Size()):
StringList.append("%s" % self._array.get(i))
if i != self.get_Size() - 1:
StringList.append(",")
StringList.append('] tail')
return "".join(StringList)
class ArrayStack(Stackbase):
def __init__(self, capacity=0):
"""默认capacity为0"""
self._array = Array(capacity)
def push(self, e):
"""向栈中添加元素"""
self._array.add_Last(e)
def pop(self):
"""从栈中取出元素"""
return self._array.remove_Last()
def peek(self):
"""获得栈顶元素"""
return self._array.get_Last()
def get_Size(self):
"""获得栈中元素数量"""
return self._array.get_Size()
def is_Empty(self):
"""栈是否为空"""
return self._array.is_Empty()
def get_capacity(self):
return self._array.get_Capacity()
def __str__(self):
StringList = []
StringList.append("Stack:size = %s, capacity = %d \n" %
(self._array.get_Size(), self._array.get_Capacity()))
StringList.append('[')
for i in range(self._array.get_Size()):
StringList.append("%s" % self._array.get(i))
if i != self._array.get_Size() - 1:
StringList.append(",")
StringList.append('] top')
return "".join(StringList)
class MaxHeap:
def __init__(self, arr=None, capacity=None):
if isinstance(arr, Array):
self._data = arr
# heapify
for i in range(self._parent(arr.get_Size() - 1), -1, -1):
self._sift_down(i)
return
if not capacity:
self._data = Array()
else:
self._data = Array(capacity)
def size(self):
"""返回堆中元素的个数"""
return self._data.get_Size()
def is_Empty(self):
"""返回布尔值，表示堆中是否为空"""
return self._data.is_Empty()
def _parent(self, index):
"""返回完全二叉树的数组表示中，一个索引所表示的元素的父节点的索引"""
if index == 0:
raise ValueError("index-0 doesn't have parent.")
return (index - 1) // 2
def _left_child(self, index):
"""返回该索引对应元素的左孩子的索引"""
return index * 2 + 1
def _right_child(self, index):
"""返回该索引对应元素的右孩子的索引"""
return index * 2 + 2
def add(self, e):
"""向堆中添加元素"""
self._data.add_Last(e) # 添加
self._sift_up(self._data.get_Size() - 1) # 上浮
def _sift_up(self, k):
"""上浮，为满足堆的大小性质"""
while k > 0 and self._data.get(self._parent(k)) < self._data.get(k):
# 不可以是根节点元素(没有父节点) & 父节点元素小于该节点元素
self._data.swap(k, self._parent(k))
k = self._parent(k)
def _find_max(self):
"""查找堆中的最大元素"""
if not self._data.get_Size():
raise ValueError("Can not find max when heap is empty.")
return self._data.get(0)
def _extract_max(self):
"""取出堆中的最大元素"""
ret = self._find_max()
self._data.swap(0, self._data.get_Size() - 1) #末尾元素与最大值交换位置
self._data.remove_Last() #删除在末尾的最大值
self._sift_down(0)
return ret
def _sift_down(self, k):
"""下移，为满足堆的大小性质"""
while self._left_child(k) < self._data.get_Size():
j = self._left_child(k)
if j + 1 < self._data.get_Size() and self._data.get(
j + 1) > self._data.get(j):
# 判断是否存在右孩子，然后判断右孩子是否大于左孩子
# data[j]是左孩子和右孩子中的最大值
j = self._right_child(k)
if self._data.get(k) >= self._data.get(j): #不大于
break
self._data.swap(k, j)
k = j
def replace(self, e):
"""取出堆中的最大元素，并且替换成元素e"""
ret = self._find_max()
self._data.set(0, e) #替换
self._sift_down(0) #下移
return ret
# for i in range(n):
# max_heap.add(random.randint(0,2000))
#
# arr = []
# for i in range(1000):
# arr.append(max_heap._extract_max())
#
# for i in range(1, 1000):
# if arr[i - 1] < arr[i]:
# raise Exception("Error")
# print("Test MaxHeap completed.")
# Test heapify
import random
n = 100000
test_arr = Array()
for i in range(n):
test_arr.add_Last(random.randint(0, 2000))
print(test_arr)
max_heap = MaxHeap(test_arr)
arr = []
for i in range(1000):
arr.append(max_heap._extract_max())
for i in range(1, 1000):
if arr[i - 1] < arr[i]:
raise Exception("Error")
print("Test MaxHeap completed.")