Time - Vicki

lib/max_subarray.rb

@@ -1,8 +1,16 @@
 
-# Time Complexity: ?
-# Space Complexity: ?
+
+# Time Complexity: O(n)
+# Space Complexity: O(n)
 def max_sub_array(nums)
     return 0 if nums == nil
-
-    raise NotImplementedError, "Method not implemented yet!"
+    max_ending_here = nums[0]
+    max_so_far = nums[0]
+
+    for i in (1..nums.length - 1 ) do 
+        max_ending_here = [nums[i], max_ending_here + nums[i]].max
+        max_so_far = [max_so_far, max_ending_here].max 
+    end 
+    return max_so_far
+
 end

lib/newman_conway.rb

@@ -1,7 +1,22 @@
 
 
-# Time complexity: ?
-# Space Complexity: ?
+# Time complexity: O(n)
+# Space Complexity: O(n)
+
+# P(n) = P(P(n - 1)) + P(n - P(n - 1)
 def newman_conway(num)
-  raise NotImplementedError, "newman_conway isn't implemented"
+  if num < 1
+    raise ArgumentError.new
+  end 
+
+  return "1" if num == 1 
+  return "1 1" if num == 2
+  result = [0,1,1]
+
+  for i in (3..num) do 
+    answer = result[result[i - 1]] + result[i - result[i - 1]]
+    result.append(answer)
+  end 
+
+  return result[1,result.length - 1].join(" ")
 end

test/max_sub_array_test.rb

@@ -1,6 +1,6 @@
 require_relative "test_helper"
 
-xdescribe "max subarray" do
+describe "max subarray" do
   it "will work for [-2,1,-3,4,-1,2,1,-5,4]" do
     # Arrange
     input = [-2,1,-3,4,-1,2,1,-5,4]