Class: String

Inherits:
Object
  • Object
show all
Defined in:
lib/uniq_char.rb

Instance Method Summary collapse

Instance Method Details

#first_uniq_char ⇒ Object 



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# File 'lib/uniq_char.rb', line 5

def first_uniq_char
  # easiest implementation to get the first char which has only one count
  # O(n^2) worst case, best 1
  #
  # Example:
  #   >> 'aabbce'.first_uniq_char
  #   => c
  #
  # Arguments:
  #
  each_char.find { |c| count(c) == 1 }
end

#first_uniq_char2 ⇒ Object 



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# File 'lib/uniq_char.rb', line 18

def first_uniq_char2
  # liner implementation
  # O(2n) worst case, best n + 1
  #
  # Example:
  #   >> 'aabbce'.first_uniq_char2
  #   => c
  #
  # could be refactor by doing just returning uniq_chars.first
  # but the best case will become 2n
  nb_count = {}
  chars.each { |c| nb_count[c] = nb_count[c].nil? ? 1 : nb_count[c] + 1 }
  couple = nb_count.find { |_k, v| v == 1 }
  # return the key of the key value couple(the first one in the couple)
  couple.nil? ? nil : couple.first
end

#uniq_chars ⇒ Object 



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# File 'lib/uniq_char.rb', line 35

def uniq_chars
  # returns list of uniq chars in a string
  # Example:
  #   >> 'aabbce'.uniq_chars
  #   => [c, e]
  #
  nb_count = {}
  uniqs = []
  chars.each { |c| nb_count[c] = nb_count[c].nil? ? 1 : nb_count[c] + 1 }
  nb_count.each { |k, v| uniqs << k if v == 1 }
  uniqs.uniq
end