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95 lines
2.6 KiB
Python
95 lines
2.6 KiB
Python
'''
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File: array_queue.py
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Created Time: 2022-11-29
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Author: Peng Chen (pengchzn@gmail.com)
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'''
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import os.path as osp
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import sys
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sys.path.append(osp.dirname(osp.dirname(osp.abspath(__file__))))
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from include import *
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""" 基于环形数组实现的队列 """
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class ArrayQueue:
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def __init__(self, size):
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self.nums = [None] * size # 用于存储队列元素的数组
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self.front = 0 # 头指针，指向队首
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self.rear = 0 # 尾指针，指向队尾 + 1
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""" 获取队列的容量 """
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def capacity(self):
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return len(self.nums)
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""" 获取队列的长度 """
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def size(self):
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# 由于将数组看作为环形，可能 rear < front ，因此需要取余数
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return (self.capacity() + self.rear - self.front) % self.capacity()
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""" 判断队列是否为空 """
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def is_empty(self):
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return len(self.nums)==0
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""" 入队 """
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def put(self, val):
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if self.size() == self.capacity():
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print("队列已满")
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return False
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# 尾结点后添加 num
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self.nums[self.rear] = val
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# 尾指针向后移动一位，越过尾部后返回到数组头部
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self.rear = (self.rear + 1) % self.capacity()
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""" 出队 """
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def get(self):
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# 删除头结点
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if self.is_empty():
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print("队列为空")
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return False
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num = self.nums[self.front]
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self.nums[self.front] = None
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# 队头指针向后移动，越过尾部后返回到数组头部
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self.front = (self.front + 1) % self.capacity()
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return num
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""" 访问队首元素 """
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def peek(self):
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# 删除头结点
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if self.is_empty():
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return 1
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return self.nums[self.front]
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""" 访问指定位置元素 """
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def get_index(self, index):
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if index >= self.size():
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return -1
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return self.nums[(self.front + index) % self.capacity()]
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if __name__ == "__main__":
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""" 初始化队列 """
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queue = ArrayQueue(5)
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""" 元素入队 """
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queue.put(1)
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queue.put(3)
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queue.put(2)
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queue.put(5)
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queue.put(4)
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print("队列 queue = ", queue.nums)
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""" 访问队首元素 """
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peek = queue.peek()
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print("队首元素 peek = ", peek)
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""" 元素出队 """
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get = queue.get()
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print("出队元素 get = ", get)
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print("出队后 queue = ", queue.nums)
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""" 获取队列的长度 """
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size = queue.size()
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print("队列长度 size = ", size)
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""" 判断队列是否为空 """
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is_empty = queue.is_empty()
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print("队列是否为空 = ", is_empty)
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