Time - Ross

lib/max_subarray.rb

@@ -1,8 +1,19 @@
 
-# Time Complexity: ?
-# Space Complexity: ?
+# Time Complexity: o(n)
+# Space Complexity: o(1)
 def max_sub_array(nums)
-    return 0 if nums == nil
+  return 0 if nums == nil
 
-    raise NotImplementedError, "Method not implemented yet!"
+  max_sum = nums[0]
+  max_ending_here = nums[0]
+
+  i = 1
+  while i < nums.length
+    max_ending_here = max_ending_here + nums[i]
+    max_ending_here = [max_ending_here, nums[i]].max
+    max_sum = [max_sum, max_ending_here].max
+    i += 1
+  end
+
+  return max_sum
 end

lib/newman_conway.rb

@@ -1,7 +1,18 @@
 
 
-# Time complexity: ?
-# Space Complexity: ?
+# Time complexity: o(n)
+# Space Complexity: o(n)
 def newman_conway(num)
-  raise NotImplementedError, "newman_conway isn't implemented"
+  raise ArgumentError if num <= 0
+  return "1" if num == 1
+  return "1 1" if num == 2
+
+  array = [0, 1, 1]
+  i = 3
+  while i <= num
+    array[i] = array[array[i - 1]] + array[i - array[i - 1]]
+    i += 1
+  end
+
+  return array[1..-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]