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146 lines
3.1 KiB
146 lines
3.1 KiB
=begin
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File: array_deque.rb
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Created Time: 2024-04-05
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Author: Xuan Khoa Tu Nguyen (ngxktuzkai2000@gmail.com)
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=end
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### 基於環形陣列實現的雙向佇列 ###
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class ArrayDeque
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### 獲取雙向佇列的長度 ###
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attr_reader :size
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### 建構子 ###
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def initialize(capacity)
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@nums = Array.new(capacity, 0)
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@front = 0
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@size = 0
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end
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### 獲取雙向佇列的容量 ###
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def capacity
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@nums.length
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end
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### 判斷雙向佇列是否為空 ###
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def is_empty?
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size.zero?
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end
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### 佇列首入列 ###
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def push_first(num)
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if size == capacity
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puts '雙向佇列已滿'
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return
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end
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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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@front = index(@front - 1)
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# 將 num 新增至佇列首
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@nums[@front] = num
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@size += 1
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end
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### 佇列尾入列 ###
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def push_last(num)
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if size == capacity
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puts '雙向佇列已滿'
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return
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end
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# 計算佇列尾指標，指向佇列尾索引 + 1
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rear = index(@front + size)
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# 將 num 新增至佇列尾
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@nums[rear] = num
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@size += 1
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end
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### 佇列首出列 ###
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def pop_first
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num = peek_first
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# 佇列首指標向後移動一位
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@front = index(@front + 1)
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@size -= 1
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num
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end
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### 佇列尾出列 ###
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def pop_last
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num = peek_last
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@size -= 1
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num
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end
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### 訪問佇列首元素 ###
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def peek_first
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raise IndexError, '雙向佇列為空' if is_empty?
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@nums[@front]
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end
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### 訪問佇列尾元素 ###
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def peek_last
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raise IndexError, '雙向佇列為空' if is_empty?
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# 計算尾元素索引
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last = index(@front + size - 1)
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@nums[last]
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end
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### 返回陣列用於列印 ###
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def to_array
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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 0...size
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res << @nums[index(@front + i)]
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end
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res
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end
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private
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### 計算環形陣列索引 ###
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def index(i)
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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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(i + capacity) % capacity
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end
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end
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### Driver Code ###
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if __FILE__ == $0
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# 初始化雙向佇列
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deque = ArrayDeque.new(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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puts "雙向佇列 deque = #{deque.to_array}"
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# 訪問元素
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peek_first = deque.peek_first
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puts "佇列首元素 peek_first = #{peek_first}"
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peek_last = deque.peek_last
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puts "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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puts "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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puts "元素 1 佇列尾入列後 deque = #{deque.to_array}"
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# 元素出列
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pop_last = deque.pop_last
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puts "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 = deque.pop_first
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puts "佇列尾出列元素 = #{pop_first}，佇列尾出列後 deque = #{deque.to_array}"
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# 獲取雙向佇列的長度
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size = deque.size
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puts "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 = deque.is_empty?
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puts "雙向佇列是否為空 = #{is_empty}"
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end
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