set1 = [[1,2],[5,7],[9,12]] set2 = [[3,4],[5,6],[13,17]] Merge the two set of interval Interview question, where the answer should be: [[1, 7], [9, 17]] There probably a corner case I'm missing somewhere. It's too early in the morning to think wah.

interval_interview_question.rb

set1 = [[1,2],[5,7],[9,12]]
set2 = [[3,4],[5,6],[13,17]]

puts set1.inspect
puts set2.inspect

puts "combind the two set"
set3 = set1 + set2
puts set3.inspect

puts "sort by lower bound"
set3 = set3.sort
puts set3.inspect

puts "merge lower bound"


def lower_bound_merge(data,pos,acc)
	if pos == (data.length)
		acc
	else 
		if acc.empty?
			if data[pos-1][1]+1 == data[pos][0]
				acc << [data[pos-1][0],data[pos][1]]
			end
				lower_bound_merge(data,pos+1,acc)
		else
			last_acc = (acc.length-1)
			if acc[last_acc][1]+1 == data[pos][0]
				acc << [acc[last_acc][0],data[pos][1]]
				acc.delete_at((last_acc))
			else
				acc << data[pos]
			end
				lower_bound_merge(data,pos+1,acc)
		end
	end
end

#lower_bound_merge(set3,1,set4)
set4 = lower_bound_merge(set3,1,Array.new())
puts set4.inspect

puts "lower bound within range merge"
def lower_bound_within_merge(data,pos,acc)
	if pos == (data.length)
		acc
	else 
		if acc.empty?
			if data[pos][0] < data[pos-1][1]
				acc << [data[pos-1][0],data[pos][1]]
			end
				lower_bound_within_merge(data,pos+1,acc)
		else
			last_acc = (acc.length-1)
			if data[pos][0] < acc[last_acc][1] 
				acc << [acc[last_acc][0],data[pos][1]]
				acc.delete_at((last_acc))
			else
				acc << data[pos]
			end
				lower_bound_within_merge(data,pos+1,acc)
		end
	end
end
set4 = lower_bound_within_merge(set4,1,Array.new())
puts set4.inspect