diff --git a/lib/max_subarray.rb b/lib/max_subarray.rb index 5204edb..d19b50d 100644 --- a/lib/max_subarray.rb +++ b/lib/max_subarray.rb @@ -1,8 +1,22 @@ -# Time Complexity: ? -# Space Complexity: ? +# Time Complexity: O(1), where n is the number of elements in the array +# Space Complexity: O(1) def max_sub_array(nums) - return 0 if nums == nil - - raise NotImplementedError, "Method not implemented yet!" + return 0 if nums == nil + + max = nums[0] + max_here = 0 + + nums.each do |num| + max_here += num + if max_here > max + max = max_here + end + + if max_here < 0 + max_here = 0 + end + end + + return max end diff --git a/lib/newman_conway.rb b/lib/newman_conway.rb index 4c985cd..a4ee82e 100644 --- a/lib/newman_conway.rb +++ b/lib/newman_conway.rb @@ -1,7 +1,34 @@ -# Time complexity: ? -# Space Complexity: ? +# Time complexity: O(n), where n is approx. equal to num +# Space Complexity: O(n), where n is approx. equal to num for the series array & series_string def newman_conway(num) - raise NotImplementedError, "newman_conway isn't implemented" -end \ No newline at end of file + if num == 0 + raise ArgumentError, "Num cannot be zero" + end + + p1 = 1 + p2 = 1 + counter = 2 + + series = [0, p1, p2] + series_string = "" + + if num < 2 + series[1..num].each do |num| + series_string += "#{num} " + end + else + until counter == num + counter += 1 + p_next = series[series[counter - 1]] + series[counter - series[counter - 1]] + series << p_next + end + + series[1..-1].each do |num| + series_string += "#{num} " + end + end + + return series_string.strip +end diff --git a/test/max_sub_array_test.rb b/test/max_sub_array_test.rb index 3253cdf..c83ef94 100644 --- a/test/max_sub_array_test.rb +++ b/test/max_sub_array_test.rb @@ -1,9 +1,9 @@ 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] + input = [-2, 1, -3, 4, -1, 2, 1, -5, 4] # Act answer = max_sub_array(input) @@ -25,7 +25,7 @@ it "will work with a totally negative array with the largest element at the rear" do # Arrange - input = [ -4, -5, -6, -7, -3] + input = [-4, -5, -6, -7, -3] # Act answer = max_sub_array(input) @@ -46,14 +46,14 @@ end it "will return nil for an empty array" do - # Arrange - input = [] + # Arrange + input = [] - # Act - answer = max_sub_array(input) + # Act + answer = max_sub_array(input) - # Assert - expect(answer).must_be_nil + # Assert + expect(answer).must_be_nil end it "will work for [50, -50, 50]" do @@ -66,5 +66,4 @@ # Assert expect(answer).must_equal 50 end - -end \ No newline at end of file +end