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authormatz <matz@b2dd03c8-39d4-4d8f-98ff-823fe69b080e>1999-08-13 05:45:20 +0000
committermatz <matz@b2dd03c8-39d4-4d8f-98ff-823fe69b080e>1999-08-13 05:45:20 +0000
commit65a5162550f58047974793cdc8067a970b2435c0 (patch)
tree082bb7d5568f3b2e36e3fe166e9f3039394fcf44 /sample/sieve.rb
parentfcd020c83028f5610d382e85a2df00223e12bd7e (diff)
1.4.0
git-svn-id: svn+ssh://ci.ruby-lang.org/ruby/trunk@520 b2dd03c8-39d4-4d8f-98ff-823fe69b080e
Diffstat (limited to 'sample/sieve.rb')
-rw-r--r--sample/sieve.rb21
1 files changed, 9 insertions, 12 deletions
diff --git a/sample/sieve.rb b/sample/sieve.rb
index 5e9f792..359c185 100644
--- a/sample/sieve.rb
+++ b/sample/sieve.rb
@@ -1,17 +1,14 @@
# sieve of Eratosthenes
-sieve = []
max = Integer(ARGV.shift || 100)
+sieve = []
+for i in 2 .. max
+ sieve[i] = i
+end
-print "1"
-for i in 2 .. max
- begin
- for d in sieve
- fail if i % d == 0
- end
- print ", "
- print i
- sieve.push(i)
- rescue
+for i in 2 .. Math.sqrt(max)
+ next unless sieve[i]
+ (i*i).step(max, i) do |j|
+ sieve[j] = nil
end
end
-print "\n"
+puts sieve.compact.join ", "