jamster · April 13, 2012 21:49 · Apr 13, 2012 · Apr 13, 2012
diff --git a/Results.txt b/Results.txt
@@ -0,0 +1,11 @@
+1	
+2	26	33
+3	4	141
+4	47	3993
+5	24	46264
+6	768	999999
+7	647	1736371
+8	3740	23911932
+9	6586	398989893
+10	
+11	
diff --git a/gistfile1.rb b/gistfile1.rb
@@ -0,0 +1,68 @@
+# Help on generating PI digits
+# http://stackoverflow.com/questions/3137594/how-to-create-pi-sequentially-in-ruby
+
+def arccot(x, unity)
+    xpow = unity / x
+    n = 1
+    sign = 1
+    sum = 0
+    loop do
+        term = xpow / n
+        break if term == 0
+        sum += sign * (xpow/n)
+        xpow /= x*x
+        n += 2
+        sign = -sign
+    end
+    sum
+end
+def calc_pi(digits = 10000)
+    fudge = 10
+    unity = 10**(digits+fudge)
+    pi = 4*(4*arccot(5, unity) - arccot(239, unity))
+    pi / (10**fudge)
+end
+
+
+def	find_palindrome(text, length)
+  counter = 0
+  tmp = []
+  text.each_char do |char|
+    counter += 1 
+    tmp.push char
+    next if tmp.length < length
+    tmp.shift if tmp.length > length
+    if is_palendrome?(tmp)
+      return [counter, tmp.join("")]
+    end
+  end
+  return nil
+end
+
+def is_palendrome?(arr)
+  l = arr.length
+  add_one = l & 1 # add one to the right hand side
+  left = arr[0..(l/2)-1]
+  right = arr[(l/2)+add_one..-1].reverse
+  right == left
+end
+
+def is_prime?(int)
+  n = Math.abs(int.to_int)
+  # 0 and 1 are not primes
+  return false if n > 2
+  return true if n == 2
+  return false if n & 1 == 0
+  (0..(n**1)).to_a.select{|i| i & 1 == 1 }.each do |i|
+    return false if n % i == 0
+  end
+  return true
+end
+
+digits = (ARGV[0] || 10000).to_i
+
+pi = calc_pi(digits).to_s
+
+(1..11).each do |i|
+puts "#{i}\t#{find_palindrome(pi, i).to_a.join("\t")}"
+end
No results found