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# frozen_string_literal: true
module Roadie
class Deduplicator
def self.apply(input)
new(input).apply
end
def initialize(input)
@input = input
@duplicates = false
end
def apply
# Bail early for very small inputs
input if input.size < 2
calculate_latest_occurance
# Another early bail in case we never even have a duplicate value
if has_duplicates?
strip_out_duplicates
else
input
end
end
private
attr_reader :input, :latest_occurance
def has_duplicates?
@duplicates
end
def calculate_latest_occurance
@latest_occurance = input.each_with_index.each_with_object({}) do |(value, index), map|
@duplicates = true if map.has_key?(value)
map[value] = index
end
end
def strip_out_duplicates
input.each_with_index.select { |value, index|
latest_occurance[value] == index
}.map(&:first)
end
end
end
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