Sha256: 7e1fae405ba7bc347d55087f4b225c09c7cc26cbe04bff34181614f8ee4a0687
Contents?: true
Size: 491 Bytes
Versions: 36
Compression:
Stored size: 491 Bytes
Contents
# coding: utf-8
class Integer
# A Carol number is an integer of the form <i>4<sup>n</sup> − 2<sup>n +
# 1</sup> − 1</i>.
#
# This method returns true if self is a Carol number; false otherwise.
#
# −1.carol? #=> true
# 959.carol? #=> true
# 32.carol? #=> false
#
def carol?
return true if self == 7
return true if self == -1
a, b = to_s(2).match(/^(1+)0(1+)$/).to_a[1..-1]
return false if (a.nil? or b.nil?)
b.length == (a.length + 3)
end
end
Version data entries
36 entries across 36 versions & 1 rubygems