diff --git a/lib/max_subarray.rb b/lib/max_subarray.rb index 5204edb..50efccc 100644 --- a/lib/max_subarray.rb +++ b/lib/max_subarray.rb @@ -1,8 +1,23 @@ - -# 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 == [] + + max_arr = nums[0] + current_max = 0 + counter = 0 + + while counter < nums.length + current_max = current_max + nums[counter] + if (max_arr < current_max) + max_arr = current_max + end + + if current_max < 0 + current_max = 0 + end + counter += 1 + end + + return max_arr end diff --git a/lib/newman_conway.rb b/lib/newman_conway.rb index 4c985cd..12e6a1d 100644 --- a/lib/newman_conway.rb +++ b/lib/newman_conway.rb @@ -1,7 +1,25 @@ +# Time complexity: O(n) +# Space Complexity: O(n) +def newman_conway(num) + if num < 1 + raise ArgumentError, "Enter a positive integer" + end + return "1" if num == 1 -# Time complexity: ? -# Space Complexity: ? -def newman_conway(num) - raise NotImplementedError, "newman_conway isn't implemented" -end \ No newline at end of file + arr = [0, 1, 1] + + sequence = "" + sequence << arr[1].to_s + " " + sequence << arr[2].to_s + " " + + counter = 3 + + while counter <= num + arr[counter] = arr[arr[counter - 1]] + arr[counter - arr[counter - 1]] + sequence << arr[counter].to_s + " " + counter += 1 + end + + return sequence[0...-1] +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