1def assert_equal(x, y)
 2  raise [x, y].inspect unless x == y
 3end
 4
 5class Solution
 6  # time: O(n)
 7  # space: O(1)
 8  def self.run(items)
 9    max = nil
10    hit = 0
11
12    for i in items
13      if max.nil?
14        max = i
15      elsif i > max
16        hit += 1
17      end
18
19      max = i
20      return false if hit > 1
21    end
22
23    true
24  end
25end
26
27assert_equal true, Solution.run([13, 4, 7])
28assert_equal false, Solution.run([5,1,3,2,5])
29
30puts 'Yay!'