Ruby

1class MyCircularQueue
2  def initialize(k)
3    @queue = Array.new(k, 0)
4    @capacity = k
5    @head = -1
6    @tail = -1
7  end
8
9  def en_queue(value)
10    return false if is_full
11    @head = 0 if is_empty
12    @tail = (@tail+1) % @capacity
13    @queue[@tail] = value
14
15    return true
16  end
17
18  def de_queue()
19    return false if is_empty
20    if @head == @tail
21      @head = -1
22      @tail = -1
23      return true
24    end
25    @head = (@head + 1) % @capacity
26    return true
27  end
28
29  def front()
30    return -1 if is_empty
31    @queue[@head]
32  end
33
34  def rear()
35    return -1 if is_empty
36    @queue[@tail]
37  end
38
39  def is_empty()
40    @head == -1
41  end
42
43  def is_full()
44    ((@tail + 1) % @capacity) == @head
45  end
46end
47