Implement Deque with Python list

最新推荐文章于 2022-05-18 08:26:47 发布

原创最新推荐文章于 2022-05-18 08:26:47 发布 · 526 阅读

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本文介绍了一种双端队列（Deque）的数据结构实现，并通过一个简单的回文检查程序展示了其用法。该实现支持从两端添加和移除元素，适用于需要高效双向操作的应用场景。

# Completed implementation of a deque ADT
class Deque:
    def __init__(self):
        self.data = []

    def is_empty(self):
        return self.data == []

    def add_front(self, item):
        self.data.append(item)

    def add_rear(self, item):
        self.data.insert(0, item)

    def remove_front(self):
        return self.data.pop()

    def remove_rear(self):
        return self.data.pop(0)

    def size(self):
        return len(self.data)

if __name__ == '__main__':
    dq = Deque()
    dq.add_front('hello')
    dq.add_front(123)
    dq.add_rear(True)
    dq.add_rear(3.14)
    while not dq.is_empty():
        print(dq.remove_front())
        print(dq.remove_rear())

A simple case to use Deque:

from deque import Deque

def pal_checker(str):
    '''Palindrome checker.
        eg. abcba is a palindrome
    '''
    ch_deque = Deque()
    for ch in str:
        ch_deque.add_front(ch)

    if ch_deque.size() < 2:   # Assume '' or only one character is palindrome
        return True

    while ch_deque.size() > 1:
        if ch_deque.remove_front() == ch_deque.remove_rear():
            continue
        else:
            break
    else:
        return True
    return False

if __name__ == '__main__':
    print(pal_checker('abcdedcba'))
    print(pal_checker('asdfghfdsa'))
    print(pal_checker('aabbcc'))
    print(pal_checker('asdfghjklkjhgfdsa'))