From 0511ac11b3bcecb70103e4a8e48ca334de3f8719 Mon Sep 17 00:00:00 2001 From: Kim Fasbender Date: Sun, 20 Oct 2019 18:57:29 -0700 Subject: [PATCH 1/4] implemented newman_conway with all tests passings --- lib/newman_conway.rb | 23 +++++++++++++---- test/newman_conway_test.rb | 51 +++++++++++++++++++------------------- 2 files changed, 43 insertions(+), 31 deletions(-) diff --git a/lib/newman_conway.rb b/lib/newman_conway.rb index 4c985cd..6bdaaff 100644 --- a/lib/newman_conway.rb +++ b/lib/newman_conway.rb @@ -1,7 +1,20 @@ - -# Time complexity: ? -# Space Complexity: ? +# Time complexity: O(n) - where n equals num - 2 +# Space Complexity: O(n) - where n equals num * 2 (for the space needed for the string and the array) def newman_conway(num) - raise NotImplementedError, "newman_conway isn't implemented" -end \ No newline at end of file + raise ArgumentError if num <= 0 + return "1" if num == 1 + + newman = [0, 1, 1] + result = "1 1" + i = 3 + + until i >= num + 1 + current_newman = newman[newman[i - 1]] + newman[i - (newman[i - 1])] + newman << current_newman + result += " #{current_newman}" + i += 1 + end + + return result +end diff --git a/test/newman_conway_test.rb b/test/newman_conway_test.rb index 537d376..5476d10 100644 --- a/test/newman_conway_test.rb +++ b/test/newman_conway_test.rb @@ -24,31 +24,30 @@ end it "works with base cases" do - # Arrange - input = 0 - - # Act-Assert - expect { - newman_conway(input) - }.must_raise ArgumentError - - - # Arrange - input = 1 - - # Act - answer = newman_conway(input) - - # Assert - expect(answer).must_equal "1" - - # Arrange - input = 2 - - # Act - answer = newman_conway(input) - - # Assert - expect(answer).must_equal "1 1" + # Arrange + input = 0 + + # Act-Assert + expect { + newman_conway(input) + }.must_raise ArgumentError + + # Arrange + input = 1 + + # Act + answer = newman_conway(input) + + # Assert + expect(answer).must_equal "1" + + # Arrange + input = 2 + + # Act + answer = newman_conway(input) + + # Assert + expect(answer).must_equal "1 1" end end From ae90e4cbdf7ee33dfe0aff39878d4b18fc75301e Mon Sep 17 00:00:00 2001 From: Kim Fasbender Date: Sun, 20 Oct 2019 18:57:43 -0700 Subject: [PATCH 2/4] implemented max_sub_array with tests passing --- lib/max_subarray.rb | 24 +++++++++++++++++++----- test/max_sub_array_test.rb | 21 ++++++++++----------- 2 files changed, 29 insertions(+), 16 deletions(-) diff --git a/lib/max_subarray.rb b/lib/max_subarray.rb index 5204edb..d55ece2 100644 --- a/lib/max_subarray.rb +++ b/lib/max_subarray.rb @@ -1,8 +1,22 @@ -# Time Complexity: ? -# Space Complexity: ? +# Time Complexity: O(n) - where n is equal to the length of nums - 1 +# Space Complexity: O(1) - constant def max_sub_array(nums) - return 0 if nums == nil - - raise NotImplementedError, "Method not implemented yet!" + return nil if nums == nil || nums.empty? + + current_sum = nums.first + max = nums.first + + (1...nums.length).each do |i| + current_sum += nums[i] + + if nums[i] > current_sum + max = nums[i] if nums[i] > max + current_sum = nums[i] + else + max = current_sum if current_sum > max + end + end + + return max 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 From 8a0ebd1c0bb1db02c819ef620035ee4739d6bffd Mon Sep 17 00:00:00 2001 From: Kim Fasbender Date: Sun, 20 Oct 2019 18:57:43 -0700 Subject: [PATCH 3/4] implemented max_subarray with all tests passing --- lib/max_subarray.rb | 25 ++++++++++++++++++++----- test/max_sub_array_test.rb | 21 ++++++++++----------- 2 files changed, 30 insertions(+), 16 deletions(-) diff --git a/lib/max_subarray.rb b/lib/max_subarray.rb index 5204edb..9603e44 100644 --- a/lib/max_subarray.rb +++ b/lib/max_subarray.rb @@ -1,8 +1,23 @@ -# Time Complexity: ? -# Space Complexity: ? +# Time Complexity: O(n) - where n is equal to the length of nums - 1 +# Space Complexity: O(1) - constant def max_sub_array(nums) - return 0 if nums == nil - - raise NotImplementedError, "Method not implemented yet!" + return nil if nums == nil || nums.empty? + + current_sum = nums.first + max = nums.first + + (1...nums.length).each do |i| + current_sum += nums[i] + + if current_sum > max + max = current_sum + end + + if current_sum < 0 + current_sum = 0 + end + end + + return max 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 From 12c8e7b965c679b327d749e685b40c97492f6fe0 Mon Sep 17 00:00:00 2001 From: Kim Fasbender Date: Sun, 20 Oct 2019 19:09:47 -0700 Subject: [PATCH 4/4] updated max_subarray for readability --- lib/max_subarray.rb | 8 -------- 1 file changed, 8 deletions(-) diff --git a/lib/max_subarray.rb b/lib/max_subarray.rb index 366417b..9603e44 100644 --- a/lib/max_subarray.rb +++ b/lib/max_subarray.rb @@ -10,20 +10,12 @@ def max_sub_array(nums) (1...nums.length).each do |i| current_sum += nums[i] -<<<<<<< HEAD if current_sum > max max = current_sum end if current_sum < 0 current_sum = 0 -======= - if nums[i] > current_sum - max = nums[i] if nums[i] > max - current_sum = nums[i] - else - max = current_sum if current_sum > max ->>>>>>> ae90e4cbdf7ee33dfe0aff39878d4b18fc75301e end end