From bc53ff36332dba9cb7b9bed17a7ab89973f53745 Mon Sep 17 00:00:00 2001 From: Kalkidan Ashenafi Date: Sat, 26 Jun 2021 18:05:56 -0700 Subject: [PATCH 1/2] newman conway implemented --- lib/newman_conway.rb | 21 +++++++++++++++++---- 1 file changed, 17 insertions(+), 4 deletions(-) diff --git a/lib/newman_conway.rb b/lib/newman_conway.rb index 4c985cd..4bdab43 100644 --- a/lib/newman_conway.rb +++ b/lib/newman_conway.rb @@ -1,7 +1,20 @@ +# Time complexity: O(n) +# Space Complexity: O(n) - -# Time complexity: ? -# Space Complexity: ? +# P(n) = P(P(n - 1)) + P(n - P(n - 1) def newman_conway(num) - raise NotImplementedError, "newman_conway isn't implemented" + if num < 1 + raise ArgumentError.new + end + + return "1" if num == 1 + return "1 1" if num == 2 + result = [0,1,1] + + for i in (3..num) do + ans = result[result[i - 1]] + result[i - result[i - 1]] + result.append(ans) + end + + return result[1,result.length - 1].join(" ") end \ No newline at end of file From 85dbdcc2da03edbfce222712516613fd91c708ff Mon Sep 17 00:00:00 2001 From: Kalkidan Ashenafi Date: Sat, 26 Jun 2021 19:02:42 -0700 Subject: [PATCH 2/2] implement max sub array, tests passing --- lib/max_subarray.rb | 19 +++++++++++++------ test/max_sub_array_test.rb | 2 +- 2 files changed, 14 insertions(+), 7 deletions(-) diff --git a/lib/max_subarray.rb b/lib/max_subarray.rb index 5204edb..2beabb2 100644 --- a/lib/max_subarray.rb +++ b/lib/max_subarray.rb @@ -1,8 +1,15 @@ - -# 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!" -end + + max_ending_here = nums[0] + max_so_far = nums[0] + + for i in (1..nums.length - 1 ) do + max_ending_here = [nums[i], max_ending_here + nums[i]].max + max_so_far = [max_so_far, max_ending_here].max + end + return max_so_far + +end \ No newline at end of file diff --git a/test/max_sub_array_test.rb b/test/max_sub_array_test.rb index 3253cdf..e27e1ca 100644 --- a/test/max_sub_array_test.rb +++ b/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]