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# CtCI 6th Edition Problem 1.6

# String Compression: Implement a method to perform basic string compression using the counts

# of repeated characters. For example, the string aabcccccaaa would become a2b1c5a3. If the

# "compressed" string would not become smaller than the original string, your method should return

# the original string. You can assume the string has only uppercase and lowercase letters (a - z).

# Loops through each character so it is O(n)

def compress_string(str)

compressed_string = ''

last_char = ''

str.each_char do |char|

unless char == last_char

# Add two characters to compressed_string: char + number.

# We will increase the number if the next character is the same as this one

compressed_string << char + '1'

last_char = char

else

# Character is the same as the last character, so increment the counter

compressed_string[-1] = (compressed_string[-1].to_i + 1).to_s

end

end

compressed_string.length < str.length ? compressed_string : str

end