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@jasl
Created May 23, 2013 18:46
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three gates
require 'securerandom'
def seed
SecureRandom.uuid.gsub(/[-a-z]/,"").to_i
end
total = 10000
rights = 0
(1..total).each do
# gen a random doors
doors = [false, false, false]
doors[Random.new(seed).rand(3)] = true
# choose a door
rights += 1 if doors[Random.new(seed).rand(3)]
end
puts "insist: rights: #{rights}, probability: #{rights.to_f / total}."
rights = 0
(1..total).each do
# gen a random doors
doors = [false, false, false]
doors[Random.new(seed).rand(3)] = true
indexes = [0, 1, 2]
# choose a door
c = Random.new(seed).rand(3)
# remove a wrong door
indexes.delete c
until indexes.length == 1
i = Random.new(seed).rand(3)
indexes.delete i unless doors[i]
end
rights += 1 if doors[indexes[0]]
end
puts "change: rights #{rights}, probability: #{rights.to_f / total}."
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