elight (owner)

Revisions

gist: 224727 Download_button fork
public
Public Clone URL: git://gist.github.com/224727.git
Embed All Files: show embed
kata_2_iterative_solution.rb #
raw 
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145

require 'test/unit'
 
def chop(target, input)
  puts "--------------------------------"
  puts "chop #{target}, #{input.inspect}"
  return -1 if input.empty? || target < 0 || target < input.first || target > input.last
  found = false
  @current_index = input.length / 2
  @current_array = input
  while !found do
    puts "current_index: #{@current_index}"
    return @current_index if target == input[@current_index]
    left, right = @current_array.split_on @current_index
    puts "#{left.inspect}, #{right.inspect}"
    if !left.empty? && target <= left.last
      go(:left, left)
    elsif !right.empty? && target >= right.first
      go(:right, right)
    else
      return -1
    end
  end
end
 
def go(direction, input)
  op = direction == :left ? "-" : "+"
  @current_index = @current_index.send(op, input.length / 2)
  @current_index = @current_index.send(op, 1) unless input.length.even?
  @current_array = input
end
 
class Fixnum
  def even?
    self % 2 == 0
  end
end
 
class Array
  def split_on(pos)
      [self[0...pos], self[pos + 1...length]]
  end
end
 
class TestChop < Test::Unit::TestCase
  def test_chop
    assert_equal(-1, chop(3, []))
    assert_equal(-1, chop(3, [1]))
    assert_equal(0,  chop(1, [1]))
    #
    assert_equal(0,  chop(1, [1, 3, 5]))
    assert_equal(1,  chop(3, [1, 3, 5]))
    assert_equal(2,  chop(5, [1, 3, 5]))
    assert_equal(-1, chop(0, [1, 3, 5]))
    assert_equal(-1, chop(2, [1, 3, 5]))
    assert_equal(-1, chop(4, [1, 3, 5]))
    assert_equal(-1, chop(6, [1, 3, 5]))
    #
    assert_equal(0,  chop(1, [1, 3, 5, 7]))
    assert_equal(1,  chop(3, [1, 3, 5, 7]))
    assert_equal(2,  chop(5, [1, 3, 5, 7]))
    assert_equal(3,  chop(7, [1, 3, 5, 7]))
    assert_equal(-1, chop(0, [1, 3, 5, 7]))
    assert_equal(-1, chop(2, [1, 3, 5, 7]))
    assert_equal(-1, chop(4, [1, 3, 5, 7]))
    assert_equal(-1, chop(6, [1, 3, 5, 7]))
    assert_equal(-1, chop(8, [1, 3, 5, 7]))
  end
end
# >> Loaded suite -
# >> Started
# >> --------------------------------
# >> chop 3, []
# >> --------------------------------
# >> chop 3, [1]
# >> --------------------------------
# >> chop 1, [1]
# >> current_index: 0
# >> --------------------------------
# >> chop 1, [1, 3, 5]
# >> current_index: 1
# >> [1], [5]
# >> current_index: 0
# >> --------------------------------
# >> chop 3, [1, 3, 5]
# >> current_index: 1
# >> --------------------------------
# >> chop 5, [1, 3, 5]
# >> current_index: 1
# >> [1], [5]
# >> current_index: 2
# >> --------------------------------
# >> chop 0, [1, 3, 5]
# >> --------------------------------
# >> chop 2, [1, 3, 5]
# >> current_index: 1
# >> [1], [5]
# >> --------------------------------
# >> chop 4, [1, 3, 5]
# >> current_index: 1
# >> [1], [5]
# >> --------------------------------
# >> chop 6, [1, 3, 5]
# >> --------------------------------
# >> chop 1, [1, 3, 5, 7]
# >> current_index: 2
# >> [1, 3], [7]
# >> current_index: 1
# >> [1], []
# >> current_index: 0
# >> --------------------------------
# >> chop 3, [1, 3, 5, 7]
# >> current_index: 2
# >> [1, 3], [7]
# >> current_index: 1
# >> --------------------------------
# >> chop 5, [1, 3, 5, 7]
# >> current_index: 2
# >> --------------------------------
# >> chop 7, [1, 3, 5, 7]
# >> current_index: 2
# >> [1, 3], [7]
# >> current_index: 3
# >> --------------------------------
# >> chop 0, [1, 3, 5, 7]
# >> --------------------------------
# >> chop 2, [1, 3, 5, 7]
# >> current_index: 2
# >> [1, 3], [7]
# >> current_index: 1
# >> [1], []
# >> --------------------------------
# >> chop 4, [1, 3, 5, 7]
# >> current_index: 2
# >> [1, 3], [7]
# >> --------------------------------
# >> chop 6, [1, 3, 5, 7]
# >> current_index: 2
# >> [1, 3], [7]
# >> --------------------------------
# >> chop 8, [1, 3, 5, 7]
# >> .
# >> Finished in 0.000834 seconds.
# >> 
# >> 1 tests, 19 assertions, 0 failures, 0 errors