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sixtyfive / armstrong.rb

Last active 1 month ago

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sixtyfive revised this gist 8 months ago · df5d2ad

1 file changed, 5 insertions, 1 deletion

armstrong.rb
@@ -94,6 +94,10 @@ class Integer
94 94 digits = self.to_s.chars.map(&:to_i)
95 95 self == digits.map{_1**digits.count}.inject(&:+)
96 96 end
97 +
98 + def skippable?
99 + self.to_s.size > 31 && self.to_s.chars.uniq.size != 10
100 + end
97 101 end
98 102
99 103 def test
@@ -104,4 +108,4 @@ def test
104 108 end
105 109 end
106 110
107 - test
111 + (1..115132219018763992565095597973971522401).each{|i| next if i.skippable?; puts i if i.is_armstrong?}

sixtyfive revised this gist 8 months ago · bdb308c

1 file changed, 107 insertions

armstrong.rb (file created)
@@ -0,0 +1,107 @@
1 + KNOWN_ARMSTRONG = [
2 + 1,
3 + 2,
4 + 3,
5 + 4,
6 + 5,
7 + 6,
8 + 7,
9 + 8,
10 + 9,
11 + 153,
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76 + 23866716435523975980390369295,
77 + 1145037275765491025924292050346,
78 + 1927890457142960697580636236639,
79 + 2309092682616190307509695338915,
80 + 17333509997782249308725103962772,
81 + 186709961001538790100634132976990,
82 + 186709961001538790100634132976991,
83 + 1122763285329372541592822900204593,
84 + 12639369517103790328947807201478392,
85 + 12679937780272278566303885594196922,
86 + 1219167219625434121569735803609966019,
87 + 12815792078366059955099770545296129367,
88 + 115132219018763992565095597973971522400,
89 + 115132219018763992565095597973971522401
90 + ]
91 +
92 + class Integer
93 + def is_armstrong?
94 + digits = self.to_s.chars.map(&:to_i)
95 + self == digits.map{_1**digits.count}.inject(&:+)
96 + end
97 + end
98 +
99 + def test
100 + numbers = KNOWN_ARMSTRONG
101 + KNOWN_ARMSTRONG.count.times{numbers << rand(KNOWN_ARMSTRONG.last)}
102 + numbers.sort.each do |x|
103 + puts "#{x} is #{'not ' unless x.is_armstrong?}an Armstrong number"
104 + end
105 + end
106 +
107 + test