Angela

lib/max_subarray.rb

@@ -1,8 +1,35 @@
 
-# Time Complexity: ?
-# Space Complexity: ?
+# Time Complexity: O(n^2) where n is size of nums
+# Space Complexity: O(n)
 def max_sub_array(nums)
     return 0 if nums == nil
-
-    raise NotImplementedError, "Method not implemented yet!"
+    return nil if nums.length == 0
+
+    size = nums.length
+    max_so_far = find_min(nums)
+
+    i = 0
+    while i < size
+      max_ending_here = 0
+      j = i
+      while j < size
+        max_ending_here = max_ending_here + nums[j]
+        if max_so_far < max_ending_here
+          max_so_far = max_ending_here
+        end
+        j += 1
+      end
+      i += 1
+    end
+    return max_so_far
+end
+
+def find_min(nums)
+    min = 0
+    nums.each do |num|
+        if num < min
+            min = num
+        end
+    end 
+    return min
 end

lib/newman_conway.rb

@@ -1,7 +1,26 @@
 
 
-# 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, "n must be >= 0" if num == 0
+
+  if num == 1 
+    return "1"
+  end
+
+  output_string = "1 1"
+  i = 3
+  while i > 2 && i <= num
+    new_num = newman_conway_helper(i)
+    output_string += " " + new_num.to_s
+    i += 1
+  end 
+
+  return output_string
+end
+
+def newman_conway_helper(num)
+  return 1 if num == 1 || num == 2
+  return newman_conway_helper( newman_conway_helper(num - 1)) + newman_conway_helper(num - newman_conway_helper(num - 1))
 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]