Created
October 8, 2015 19:22
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class Triplet | |
# Class methods | |
# these generate Triplet _instances_ | |
def self.up_to max | |
valid = [] | |
(1..max).each do |x| | |
y = x+1 | |
z = y+1 | |
while z <= max do | |
z += 1 while z**2 < x**2 + y**2 | |
test = Triplet.new(x, y, z) | |
valid << test if test.pythagorean? | |
y += 1 | |
end | |
end | |
valid | |
end | |
def self.where opts = {} | |
matches = [] | |
if opts[:max_factor].present? | |
matches = self.up_to(opts[:max_factor]) | |
end | |
if opts[:min_factor].present? | |
matches.reject!{ |m| m.min_factor < opts[:min_factor] } | |
end | |
if opts[:sum].present? | |
matches.select!{ |m| m.sum == opts[:sum] } | |
end | |
matches | |
end | |
# Instance methods | |
# these provide functionality to triplet _instances_ | |
def initialize a, b, c | |
@a, @b, @c = a, b, c | |
@items = [@a, @b, @c] | |
end | |
def min_factor | |
@a | |
end | |
def max_factor | |
@z | |
end | |
def sum | |
@items.inject(:+) | |
end | |
def product | |
@items.inject(:*) | |
end | |
def pythagorean? | |
@a**2 + @b**2 == @c**2 | |
end | |
end |
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