exercism 57

Author: kumar91gopi

Diff for: README.md

@@ -274,6 +274,7 @@ solution of many challenges of [Leetcode](https://leetcode.com/), [Exercism](htt
 54. [Nucleotide Count](https://github.com/kumar91gopi/Algorithms-and-Data-Structures-in-Ruby/blob/master/exercism/nucleotide_count.rb)
 55. [Pythogorean Triplet](https://github.com/kumar91gopi/Algorithms-and-Data-Structures-in-Ruby/blob/master/exercism/pythogorean_triplet.rb)
 56. [Collatz Conjecture](https://github.com/kumar91gopi/Algorithms-and-Data-Structures-in-Ruby/blob/master/exercism/collatz_conjecture.rb)
+57. [Seive](https://github.com/kumar91gopi/Algorithms-and-Data-Structures-in-Ruby/blob/master/exercism/seive.rb)
 
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Diff for: exercism/seive.rb

@@ -0,0 +1,37 @@
+#Problem: https://exercism.org/tracks/ruby/exercises/sieve
+
+#Solution
+class Sieve
+    def initialize(num)
+      if num>1
+        @input=(2..num).to_a 
+      else
+        @input=[]
+      end
+    end
+
+    def primes
+      return [] if @input==[]
+      primes=[]
+      @input.each do |num|
+        next if num==nil
+        primes.append(num)
+        @input.map! {|x| x=x if x!=nil && x%num!=0 }
+      end
+      primes
+    end  
+end
+
+#Solution 2
+class Sieve
+    def initialize(top)
+      @top = top
+    end
+    def primes
+      numbers = [nil, nil, *2..@top]
+      (2..Math.sqrt(@top)).each do |i|
+        (i**2..@top).step(i) { |m| numbers[m] = nil } if numbers[i]
+      end
+      numbers.compact
+    end
+end