Erica

lib/max_subarray.rb

@@ -1,8 +1,21 @@
 
-# Time Complexity: ?
-# Space Complexity: ?
+# Time Complexity: O(n), where n is the number of items in nums
+# 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 = nums[0]
+  current_max = 0
+  count = 0
+
+  while count < nums.length
+    current_max = current_max + nums[count]
+
+    max = current_max if max < current_max
+    current_max = 0 if current_max < 0
+
+    count += 1
+  end
+
+  return max
 end

lib/newman_conway.rb

@@ -1,7 +1,26 @@
+# Time complexity: O(n), where n is directly proportional to the size of num
+# Space Complexity: O(n), where n is directly proportional to the size of num
+def newman_conway(num)
+  if num <= 0 
+    raise ArgumentError, "Must pass in integer greater than zero, received: #{num}" 
+  end 
 
+  hash = {1 => 1, 2 => 1}
+  result = []
+  count = 1
 
-# Time complexity: ?
-# Space Complexity: ?
-def newman_conway(num)
-  raise NotImplementedError, "newman_conway isn't implemented"
+  while count <= num 
+    if count == 1 || count == 2 
+      result.push(1)
+    else 
+      last = hash[count - 1] 
+      current = hash[last] + hash[count - last]
+      hash[count] = current 
+      result.push(current) 
+    end 
+
+    count += 1
+  end
+
+  return result.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]