CF_teeshirt

code.rb

=begin
CodeFights expands their t-shirt selection so that there is one color corresponding to each level (Gray/Recruit, Green/Trainee, Blue/Soldier, Yellow/Warrior, Red/Captain, Black/Ninja).

At the beginning of each month CodeFights receives a shipment of n t-shirts. There will always be an equal number of each color. Each user can only choose between 2 different colors when ordering a t-shirt. At the end of each month CodeFights takes all received orders and sends t-shirts, but only if it is possible to grant all requests. This explains why the process sometimes takes longer than expected (just teasing ^_^).

Given n and the list of orders placed, determine if CodeFights has enough t-shirts to fulfill all orders (true) or must wait until the next month (false).

Example

For n = 6 and orders = [["Red", "Black"],["Red", "Black"]],
the output should be
codefightsTshirts(n, orders) = true.

CodeFights has 6 shirts in stock, which means 1 of each color. If they send a red t-shirt for the first order, we can still send a black t-shirt for the second order. Thus, both orders can be fulfilled.

For n = 6 and
orders = [["Red", "Black"], ["Red", "Black"], ["Red", "Black"]]
the output should be
codefightsTshirts(n, orders) = false.

Again, there is 1 t-shirt of each color. It is possible to fulfill the first two orders by sending 1 red and 1 black shirt, however there won't be any red/black shirts to fulfill the third order. Thus, it's impossible to fulfill all orders this month.

For n = 6 and
orders = [["Red", "Black"], ["Blue", "Black"], ["Red", "Blue"]]
the output should be
codefightsTshirts(n, orders) = true.
first order is black, second order blue and third order is red
=end

def codefightsTshirts(n, orders)
    tees,count= n/6, {} 
    backup = Hash.new([])
    ["Gray", "Green", "Blue", "Yellow", "Red", "Black"].map {|c| count[c] = tees }
    orders.each do |order|
       if count[order[0]] > 0           
           count[order[0]] -= 1
           backup[order[0]] << order[1]  
        elsif count[order[1]] > 0
           count[order[1]] -= 1
        else
           found = false
           while backup[order[0]].count > 0
               color = backup[order[0]].pop
               if count[color] > 0
                   count[color] -= 1
                   found = true 
               end
           end

            while found == false && backup[order[1]].count > 0
               color = backup[order[1]].pop
                if count[color]  > 0
                   count[color] -= 1
                   found = true 
               end
           end
           return false if found == false
      end
    end
    return true
end

damn, ok my approach is wrong, figured out the hidden test case that was failing - added to the last of the comments - so apparently the order within the array does not matter