60 lines
1.0 KiB
Crystal
60 lines
1.0 KiB
Crystal
# miscellaneous stuff
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require "big"
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module Euler
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alias NumType = Int32 | Int64 | UInt32 | UInt64 | BigInt
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def self.trial_division(n : NumType)
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factors = [] of NumType
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check = ->(p: NumType) {
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q, r = n.divmod(p)
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while r.zero?
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factors << p
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n = q
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q, r = n.divmod(p)
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end
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}
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check.call(2)
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check.call(3)
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p = 5
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while p * p <= n
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check.call(p)
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p += 2
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check.call(p)
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p += 4
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end
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factors << n if n > 1
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factors
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end
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def self.prime_factorization(n : NumType)
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result = {} of NumType => NumType
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factors = self.trial_division(n)
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factors.each do |f|
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result[f] = 0
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num = n
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while num % f == 0
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result[f] += 1
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num /= f
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end
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end
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result
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end
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def self.palindrome?(x)
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x.to_s.reverse == x.to_s
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end
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def self.to_digit_list(n : NumType)
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n.to_s.chars.map { |d| d.to_i }
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end
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def self.to_big_ints(num_list : Array(NumType))
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num_list.map { |n| BigInt.new(n) }
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end
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end
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