tst.rb

css =  [[1, 60] ,[3, 95]]
customers = [[1, 90], [2, 20], [3, 70], [4, 40], [5, 60], [6, 10]]
vacant_css = [2, 4]


def can_answer?(cs, customer)
    cs[1] >= customer[1]
end

def most_free(candidates, allocation)
    counter = {}
    relevant_allocation = allocation.select{ |a| candidates.include? a[0] }
    candidates.each do |c|
        counter[c] = 0 if counter[c].nil?
        relevant_allocation.each do |a|
          counter[c] += 1 if a[0] == c
        end
    end
    counter.sort_by{ |k, v| v }.first[0]
end

def csRush(css, customers, vacant_css)
    active_cs_agents = css.select{ |k, v| !vacant_css.include? k }.sort_by{ |k, v| v }.reverse!
    customers.sort_by!{ |k, v| v }.reverse!

    allocation = []

    customers.each do |customer|
        css_able_to_answer = active_cs_agents.select{ |cs| can_answer?(cs, customer) }.map{ |cs| cs[0] }
        answerer = most_free(css_able_to_answer, allocation)
        allocation << [answerer, customer[0]]
    end

    counter = {}
    allocation.each do |a|
        counter[a[0]] = 0 if counter[a[0]].nil?
        counter[a[0]] += 1
    end


    counter = counter.sort_by{ |k, v| -v }
    return counter[0][1] == counter[1][1] ? 0 : counter[0][0]
end

puts csRush(css, customers, vacant_css)