Space - Katie

lib/max_subarray.rb

@@ -1,8 +1,23 @@
 
-# Time Complexity: ?
-# Space Complexity: ?
+# Time Complexity: O(n)
+# Space Complexity: O(1)
 def max_sub_array(nums)
-    return 0 if nums == nil
-
-    raise NotImplementedError, "Method not implemented yet!"
+    return nil if nums.empty?
+    max_so_far = nums[0]
+    max_ending_here = nums[0]
+
+    nums.each_with_index do |num, index|
+        if index != 0
+            max_ending_here += num
+            if(max_ending_here < num)
+                max_ending_here = num
+            end
+
+            if(max_so_far < max_ending_here)
+                max_so_far = max_ending_here
+            end
+        end
+    end
+
+    return max_so_far
 end

lib/newman_conway.rb

@@ -1,7 +1,25 @@
 
 
-# Time complexity: ?
-# Space Complexity: ?
+# Time complexity: O(n)
+# Space Complexity: O(n)
 def newman_conway(num)
-  raise NotImplementedError, "newman_conway isn't implemented"
-end
+  if(num < 1)
+    raise ArgumentError
+  elsif(num == 1)
+    return "1"
+  elsif(num == 2)
+    return "1 1"
+  end
+
+  array = [0, 1, 1]
+  while array.length <= num
+    array.push(array[array[array.length - 1]] + array[array.length - array[array.length - 1]])
+  end
+
+  return array[1..array.length].join(" ")
+end
+
+# P(1) = 1
+# P(2) = 1
+# for all n > 2
+# P(n) = P(P(n - 1)) + P(n - P(n - 1))

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]