/112.lua

 1-- solved
 2
 3function is_bouncy(n)
 4  local s = tostring(n)
 5  local sl = string.len(s)
 6  local i
 7  local dir = 0
 8  local p = string.byte(s, 1)
 9  for i = 2, sl do
10    local p2 = string.byte(s, i)
11    if p2>p then
12      if dir<0 then return true end
13      dir = 1
14    elseif p2<p then
15      if dir>0 then return true end
16      dir = -1
17    end
18    p = p2
19  end
20  return false
21end
22
23assert(is_bouncy(1232))
24assert(not is_bouncy(1233))
25
26a=100
27b=0
28
29for i=101,10000000 do
30  if not is_bouncy(i) then
31    a = a + 1
32  else
33    b = b + 1
34  end
35  if (a/(a+b))<=0.01 then
36    print(i, a, b, a/(a+b))
37    break
38  end
39end