Shubha 🧟‍♀️

lib/max_subarray.rb

@@ -1,8 +1,18 @@
 
-# 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 == nil || nums.empty?
+    max = nums[0]
+    curr_max = nums[0]
+    (1...nums.length).each do |i|
+        curr_max = curr_max + nums[i]
+        if nums[i] > curr_max
+            max = nums[i] if nums[i] > max
+            curr_max = nums[i]
+        else
+            max = curr_max if curr_max > max
+        end
+    end
+    return max
 end

lib/newman_conway.rb

@@ -1,7 +1,13 @@
 
 
-# Time complexity: ?
-# Space Complexity: ?
+# Time complexity: O(n)
+# Space Complexity: O(n)
 def newman_conway(num)
-  raise NotImplementedError, "newman_conway isn't implemented"
+  seq = [0, 1, 1]
+  raise ArgumentError if num <= 0
+  return seq[1..num].join(' ')if num == 1 || num == 2
+  (3..num).each do |i|
+    seq[i] = seq[seq[i-1]] + seq[i - seq[i - 1]]
+  end
+  return seq[1..num].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]