Анджелин обнови решението на 25.10.2015 23:26 (преди над 8 години)
+class RationalSequence
+ include Enumerable
+
+ def initialize(limit)
+ @limit = limit
+ @rising, @finished = true, true
+ @num, @denom = 1, 1
+ end
+
+ def each
+ current = Rational(@num, @denom)
+ total = [current]
+
+ yield current if @limit != 0
+
+ while total.count < @limit
+ current = iteration(total)
+
+ unless total.include? current
+ yield current
+ total << current
+ end
+ end
+ end
+
+ def iteration(total)
+ if @rising and @finished
+ @num += 1
+ @rising = false
+ elsif @finished
+ @denom += 1
+ @rising = true
+ end
+
+ if @finished
+ @finished = false
+ return Rational(@num, @denom)
+ end
+
+ @num, @denom = new_num_denom()
+
+ @finished = true if @num == 1 or @denom == 1
+ Rational(@num, @denom)
+ end
+
+ def generate_parts()
+ @rising ? [@num + 1, @denom - 1] : [@num - 1, @denom + 1]
+ end
+end
+
+class Integer
+ def prime?
+ return true if self == 2
+ return false if self % 2 == 0 or self < 2
+
+ (3..self-1).step(2) { |current| return false if self % current == 0 }
+ true
+ end
+end
+
+class PrimeSequence
+ include Enumerable
+
+ def initialize(limit)
+ @limit = limit
+ end
+
+ def each
+ current, total = 2, 0
+
+ while total < @limit
+ if current.prime?
+ yield current
+ total += 1
+ end
+
+ current += 1
+ end
+ end
+end
+
+class FibonacciSequence
+ include Enumerable
+
+ def initialize(limit, first: 1, second: 0)
+ @limit = limit
+ @first = first
+ @second = second
+ end
+
+ def each
+ current, previous = @first, @second
+ total = 0
+
+ while total < @limit
+ yield current
+ current, previous = current + previous, current
+ total += 1
+ end
+ end
+end
+
+module DrunkenMathematician
+ module_function
+
+ def meaningless(n)
+ rationals = RationalSequence.new(n).to_a
+ primes = rationals.select { |rat| rat.numerator.prime? or rat.denominator.prime? }
+ not_primes = rationals - primes
+
+ primes_sum = primes.reduce { |a, b| a*b }
+ primes_sum = 1 if not primes_sum
+
+ primes_sum / not_primes.reduce { |a, b| a*b }
+ end
+
+ def aimless(n)
+ primes = PrimeSequence.new(n).to_a
+ primes = primes.each_slice(2).to_a
+
+ primes[-1] << 1 if primes[-1].count == 1
+ rationals = primes.map { |prime| Rational(prime[0], prime[1]) }
+ rationals.reduce { |a, b| a + b }
+ end
+
+ def worthless(n)
+ nth_fibonacci = FibonacciSequence.new(n).to_a[-1]
+ rationals = RationalSequence.new(n).to_a
+
+ sum = rationals.reduce { |a, b| a + b }
+ while sum > nth_fibonacci
+ rationals.pop
+ sum = rationals.reduce { |a, b| a + b }
+ end
+
+ rationals
+ end
+end