Branches - Eve

lib/max_subarray.rb

@@ -1,8 +1,21 @@
-
-# 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!"
+  result = nil
+  if nums == nil
+    result = 0
+  elsif nums.length > 0
+    max_so_far = 0
+    max_ending_here = 0
+    largest_element = nums[0]
+    nums.each do |element|
+      max_ending_here = max_ending_here + element
+
+      max_ending_here = 0 if max_ending_here < 0
+      max_so_far = max_ending_here if max_so_far < max_ending_here        
+      largest_element = element if element > largest_element
+    end
+    result = (largest_element < 0) ? largest_element : max_so_far
+  end
+  return result
 end

lib/newman_conway.rb

@@ -1,7 +1,15 @@
-
-
-# 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 < 1
+  output = Array.new()
+  num.times do |i|
+    if i < 2
+      output << 1
+    else
+      previous = output[i - 1]
+      output << output[previous - 1] + output[i - previous]
+    end
+  end
+  return output.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]