Description:

Given a string of integers, count how many times that integer repeats itself, then return a string showing the count and the integer.

Example: countMe('1123') (count_me in Ruby)

• Here 1 comes twice so <count><integer> will be "21"
• then 2 comes once so <count><integer> will be "12"
• then 3 comes once so <count><integer> will be "13"

hence output string will be "211213".

Similarly countMe('211213') will return '1221121113' (1 time 2, 2 times 1, 1 time 2, 1 time 1, 1 time 3)

Return "" for empty, nil or non numeric strings

Test Case:

Test.expect(count_me('1123') == '211213')
Test.expect(count_me('1') == '11')
Test.expect(count_me('211213') == '1221121113')
Test.expect(count_me('a123') == '')

Solution:

def count_me(data)
  return '' if data.to_i.to_s != data
  data_s = data.to_s
  count = 1
  output = ""
  
  i = 0
  while i < data_s.length - 1
    if data_s[i] == data_s[i + 1]
      count += 1
    else 
      output << count.to_s << data_s[i]
      count = 1
    end
    
    i += 1
  end
  
   output << count.to_s << data_s[i]
end