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130 lines
3.9 KiB
130 lines
3.9 KiB
"""
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File: array_deque.py
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Created Time: 2023-03-01
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Author: krahets (krahets@163.com)
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"""
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class ArrayDeque:
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"""基於環形陣列實現的雙向佇列"""
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def __init__(self, capacity: int):
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"""建構子"""
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self._nums: list[int] = [0] * capacity
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self._front: int = 0
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self._size: int = 0
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def capacity(self) -> int:
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"""獲取雙向佇列的容量"""
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return len(self._nums)
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def size(self) -> int:
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"""獲取雙向佇列的長度"""
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return self._size
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def is_empty(self) -> bool:
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"""判斷雙向佇列是否為空"""
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return self._size == 0
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def index(self, i: int) -> int:
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"""計算環形陣列索引"""
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# 透過取餘操作實現陣列首尾相連
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# 當 i 越過陣列尾部後，回到頭部
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# 當 i 越過陣列頭部後，回到尾部
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return (i + self.capacity()) % self.capacity()
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def push_first(self, num: int):
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"""佇列首入列"""
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if self._size == self.capacity():
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print("雙向佇列已滿")
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return
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# 佇列首指標向左移動一位
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# 透過取餘操作實現 front 越過陣列頭部後回到尾部
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self._front = self.index(self._front - 1)
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# 將 num 新增至佇列首
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self._nums[self._front] = num
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self._size += 1
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def push_last(self, num: int):
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"""佇列尾入列"""
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if self._size == self.capacity():
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print("雙向佇列已滿")
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return
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# 計算佇列尾指標，指向佇列尾索引 + 1
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rear = self.index(self._front + self._size)
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# 將 num 新增至佇列尾
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self._nums[rear] = num
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self._size += 1
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def pop_first(self) -> int:
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"""佇列首出列"""
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num = self.peek_first()
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# 佇列首指標向後移動一位
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self._front = self.index(self._front + 1)
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self._size -= 1
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return num
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def pop_last(self) -> int:
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"""佇列尾出列"""
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num = self.peek_last()
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self._size -= 1
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return num
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def peek_first(self) -> int:
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"""訪問佇列首元素"""
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if self.is_empty():
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raise IndexError("雙向佇列為空")
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return self._nums[self._front]
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def peek_last(self) -> int:
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"""訪問佇列尾元素"""
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if self.is_empty():
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raise IndexError("雙向佇列為空")
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# 計算尾元素索引
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last = self.index(self._front + self._size - 1)
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return self._nums[last]
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def to_array(self) -> list[int]:
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"""返回陣列用於列印"""
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# 僅轉換有效長度範圍內的串列元素
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res = []
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for i in range(self._size):
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res.append(self._nums[self.index(self._front + i)])
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return res
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"""Driver Code"""
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if __name__ == "__main__":
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# 初始化雙向佇列
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deque = ArrayDeque(10)
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deque.push_last(3)
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deque.push_last(2)
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deque.push_last(5)
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print("雙向佇列 deque =", deque.to_array())
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# 訪問元素
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peek_first: int = deque.peek_first()
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print("佇列首元素 peek_first =", peek_first)
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peek_last: int = deque.peek_last()
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print("佇列尾元素 peek_last =", peek_last)
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# 元素入列
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deque.push_last(4)
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print("元素 4 佇列尾入列後 deque =", deque.to_array())
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deque.push_first(1)
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print("元素 1 佇列首入列後 deque =", deque.to_array())
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# 元素出列
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pop_last: int = deque.pop_last()
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print("佇列尾出列元素 =", pop_last, "，佇列尾出列後 deque =", deque.to_array())
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pop_first: int = deque.pop_first()
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print("佇列首出列元素 =", pop_first, "，佇列首出列後 deque =", deque.to_array())
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# 獲取雙向佇列的長度
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size: int = deque.size()
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print("雙向佇列長度 size =", size)
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# 判斷雙向佇列是否為空
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is_empty: bool = deque.is_empty()
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print("雙向佇列是否為空 =", is_empty)
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