gistfile1.rb

def histogram(numbers)
  hist = {}
  numbers.each do |n|
    hist[n] = 0 if hist[n].nil?
    hist[n] += 1
  end
  hist
end

#
# Returns the index of the 
#
def quantiles(histogram, percentage)
  quantiles = []
  
  sum = histogram.values.inject(0){|n, i| n += i} 
  
  total = 0
  histogram.keys.sort.each do |key|
    total += histogram[key]
    quantiles << key if total >= ((quantiles.length * percentage) * sum)
  end
    
  quantiles
end

numbers = []
0.upto(100) do |i| 
  numbers << i
end

#[0, 0, 0, 0, 0, 1, 1, 1, 1, 2, 2, 2, 3, 3, 4, 5]

hist = histogram(numbers)
puts quantiles(hist, 0.25)