From 4b5932dd67d1e97a5533bb89b88d7b35c66d0f04 Mon Sep 17 00:00:00 2001 From: "Haben Foto (Third Sector New England Inc)" Date: Thu, 8 Oct 2020 22:06:52 -0700 Subject: [PATCH 1/7] added new_conway method --- lib/newman_conway.rb | 16 +++++++++++++++- 1 file changed, 15 insertions(+), 1 deletion(-) diff --git a/lib/newman_conway.rb b/lib/newman_conway.rb index 4c985cd..d8ab40d 100644 --- a/lib/newman_conway.rb +++ b/lib/newman_conway.rb @@ -3,5 +3,19 @@ # Time complexity: ? # Space Complexity: ? def newman_conway(num) - raise NotImplementedError, "newman_conway isn't implemented" + raise ArgumentError if num <= 0 + return "1" if num == 1 + return "1 1" if num == 2 + + new_array = [0, 1, 1] + i = 3 + + while i <= num + new_array[i] = new_array[new_array[i - 1]] + new_array[i - new_array[i - 1]] + + index += 1 + end + + return new_array(1..-1) + end \ No newline at end of file From 56d27922e98603e29e373bfc888d84d2c4dbec58 Mon Sep 17 00:00:00 2001 From: "Haben Foto (Third Sector New England Inc)" Date: Thu, 8 Oct 2020 22:13:54 -0700 Subject: [PATCH 2/7] updated newman_conway method --- lib/newman_conway.rb | 6 +++--- 1 file changed, 3 insertions(+), 3 deletions(-) diff --git a/lib/newman_conway.rb b/lib/newman_conway.rb index d8ab40d..cc1408a 100644 --- a/lib/newman_conway.rb +++ b/lib/newman_conway.rb @@ -13,9 +13,9 @@ def newman_conway(num) while i <= num new_array[i] = new_array[new_array[i - 1]] + new_array[i - new_array[i - 1]] - index += 1 + i += 1 end - - return new_array(1..-1) + + return new_array.delete_at(0).join(" ") end \ No newline at end of file From 99b96ef6a1ee96dd8f35164efa42a42ac975fd7a Mon Sep 17 00:00:00 2001 From: "Haben Foto (Third Sector New England Inc)" Date: Thu, 8 Oct 2020 22:19:06 -0700 Subject: [PATCH 3/7] last update --- lib/newman_conway.rb | 6 +++--- 1 file changed, 3 insertions(+), 3 deletions(-) diff --git a/lib/newman_conway.rb b/lib/newman_conway.rb index cc1408a..c6cf23c 100644 --- a/lib/newman_conway.rb +++ b/lib/newman_conway.rb @@ -1,7 +1,7 @@ -# Time complexity: ? -# Space Complexity: ? +# Time complexity: O(n) +# Space Complexity: O(n) def newman_conway(num) raise ArgumentError if num <= 0 return "1" if num == 1 @@ -16,6 +16,6 @@ def newman_conway(num) i += 1 end - return new_array.delete_at(0).join(" ") + return new_array[1..-1].join(" ") end \ No newline at end of file From b4ec538f3bc989d5da68c050e110331dca2a78ec Mon Sep 17 00:00:00 2001 From: Haben Date: Tue, 17 Nov 2020 10:54:06 -0800 Subject: [PATCH 4/7] add max_sub_array method --- lib/max_subarray.rb | 16 ++++++++++++++-- 1 file changed, 14 insertions(+), 2 deletions(-) diff --git a/lib/max_subarray.rb b/lib/max_subarray.rb index 5204edb..ee3446e 100644 --- a/lib/max_subarray.rb +++ b/lib/max_subarray.rb @@ -3,6 +3,18 @@ # Space Complexity: ? def max_sub_array(nums) return 0 if nums == nil - - raise NotImplementedError, "Method not implemented yet!" + + max_so_far = nums[0] + curr_max = nums[0] + arr_size = nums.size + + for i in 1...arr_size + curr_max = (nums[i] > curr_max+nums[i]) ? nums[i] : curr_max+nums[i] + max_so_far = (max_so_far > curr_max) ? max_so_far : curr_max + end + + max_so_far + end + + From 59045cd530cc8a4e951981e86f56896e6cb0fa96 Mon Sep 17 00:00:00 2001 From: Haben Date: Tue, 17 Nov 2020 10:54:46 -0800 Subject: [PATCH 5/7] max_sub_array_test passing --- test/max_sub_array_test.rb | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) 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] From 6895d2bf1ee321ba796c15f0d42cb55f70b4e76c Mon Sep 17 00:00:00 2001 From: Haben Date: Tue, 17 Nov 2020 11:16:52 -0800 Subject: [PATCH 6/7] update max_sub_array method --- lib/max_subarray.rb | 26 ++++++++++++-------------- 1 file changed, 12 insertions(+), 14 deletions(-) diff --git a/lib/max_subarray.rb b/lib/max_subarray.rb index ee3446e..11095ae 100644 --- a/lib/max_subarray.rb +++ b/lib/max_subarray.rb @@ -1,20 +1,18 @@ +# frozen_string_literal: true -# Time Complexity: ? -# Space Complexity: ? -def max_sub_array(nums) - return 0 if nums == nil +# Time Complexity: O(n) +# Space Complexity: O(1) - max_so_far = nums[0] - curr_max = nums[0] - arr_size = nums.size +def max_sub_array(nums) + return nil if nums.nil? || nums.empty? - for i in 1...arr_size - curr_max = (nums[i] > curr_max+nums[i]) ? nums[i] : curr_max+nums[i] - max_so_far = (max_so_far > curr_max) ? max_so_far : curr_max - end + max_so_far = nums[0] + curr_max = nums[0] - max_so_far + nums[1..].each do |curr_num| + curr_max = [curr_num, curr_num + curr_max].max + max_so_far = [curr_max, max_so_far].max + end + max_so_far end - - From 9c40385a063af4a7c30cf2630bc5d8cd27d3fa26 Mon Sep 17 00:00:00 2001 From: Haben Date: Tue, 17 Nov 2020 11:17:12 -0800 Subject: [PATCH 7/7] add time and space complexity --- lib/newman_conway.rb | 15 +++++++-------- 1 file changed, 7 insertions(+), 8 deletions(-) diff --git a/lib/newman_conway.rb b/lib/newman_conway.rb index c6cf23c..8959d75 100644 --- a/lib/newman_conway.rb +++ b/lib/newman_conway.rb @@ -1,21 +1,20 @@ - +# frozen_string_literal: true # Time complexity: O(n) # Space Complexity: O(n) def newman_conway(num) raise ArgumentError if num <= 0 - return "1" if num == 1 - return "1 1" if num == 2 + return '1' if num == 1 + return '1 1' if num == 2 new_array = [0, 1, 1] i = 3 - + # P(P(n - 1)) + P(n - P(n - 1)) while i <= num new_array[i] = new_array[new_array[i - 1]] + new_array[i - new_array[i - 1]] - + i += 1 end - return new_array[1..-1].join(" ") - -end \ No newline at end of file + new_array[1..].join(' ') +end