string-rearrengement.rb

#!usr/bin/ruby

# Given a comma-separated list of equal-length strings, check if it is possible to rearrange the strings in such a way that after the rearrangement the strings at consecutive positions would differ by exactly one character.

# Example

# For input: aba,bbb,bab the output should be: false

# For input: ab,bb,aa the output should be: true

# Input Format

# A comma-separated list of strings containing alphanumeric characters.

# Constraints

# 2 ≤ list length ≤ 10
# 1 ≤ string length ≤ 15.
# Output Format

# Either the string true or false

# Sample Input 0

# aba,bbb,bab
# Sample Output 0

# false 
# Sample Input 1

# ab,bb,aa
# Sample Output 1

# true
# Sample Input 2

# q,q
# Sample Output 2

# false
# Sample Input 3

# zzzzab,zzzzbb,zzzzaa
# Sample Output 3

# true

class Rearrengement
  attr_accessor :collection

  def initialize
    input = clean_params(gets.chop, ',')
    @collection = []
    for i in input
      @collection << i
    end
    @num_elems = @collection.size
    @res = []
  end

  def verify
    return @num_elems == @res.size
  end

  def order
    @res = [@collection[0]]
    reduce(0)
    change = true
    while(change && @collection.size!=0) do
      for i in 0..@collection.size-1
        if(insert_in_sides(@collection[i]))
          reduce(i)
          change = true
          break
        else
          change = false
        end
      end
      change &= change
    end
  end

  private

  def reduce(i)
    @collection[i] = nil
    @collection.compact!
  end

  def insert_in_sides(word)
    if(similar(word, @res[0], 1))
      @res.unshift(word)
      return true
    end
    if(similar(word, @res[@res.length-1], 1))
      @res << word
      return true
    end
    return false
  end

  def clean_params(str, separator = '')
    str.split(separator)
  end

  def similar(word1, word2, mistakes_allowed)
    for i in 0..word1.length-1 do
      if(word1[i] != word2[i])
        mistakes_allowed-=1
      end
    end
    if(mistakes_allowed == 0)
      return true
    else
      return false
    end
  end

  def swap(i,j)
    return if(i == j)
    tmp = @collection[i]
    @collection[i] = @collection[j]
    @collection[j] = tmp
  end
end

r = Rearrengement.new
r.order
puts r.verify