From eb87324eebabab5a7fc0d5769210ffe3d24b1ece Mon Sep 17 00:00:00 2001 From: Katie Date: Tue, 5 Jan 2021 19:43:06 -0800 Subject: [PATCH 1/2] implemented methods --- lib/max_subarray.rb | 25 ++++++++++++++++++++----- lib/newman_conway.rb | 22 ++++++++++++++++++++-- test/max_sub_array_test.rb | 2 +- 3 files changed, 41 insertions(+), 8 deletions(-) diff --git a/lib/max_subarray.rb b/lib/max_subarray.rb index 5204edb..3aff68a 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.empty? + max_so_far = nums[0] + max_ending_here = nums[0] + + nums.each_with_index do |num, index| + if index != 0 + max_ending_here += num + if(max_ending_here < num) + max_ending_here = num + end + + if(max_so_far < max_ending_here) + max_so_far = max_ending_here + end + end + end + + return max_so_far end diff --git a/lib/newman_conway.rb b/lib/newman_conway.rb index 4c985cd..d1b12d5 100644 --- a/lib/newman_conway.rb +++ b/lib/newman_conway.rb @@ -3,5 +3,23 @@ # Time complexity: ? # Space Complexity: ? def newman_conway(num) - raise NotImplementedError, "newman_conway isn't implemented" -end \ No newline at end of file + if(num < 1) + raise ArgumentError + elsif(num == 1) + return "1" + elsif(num == 2) + return "1 1" + end + + array = [0, 1, 1] + while array.length <= num + array.push(array[array[array.length - 1]] + array[array.length - array[array.length - 1]]) + end + + return array[1..array.length].join(" ") +end + +# P(1) = 1 +# P(2) = 1 +# for all n > 2 +# P(n) = P(P(n - 1)) + P(n - P(n - 1)) \ 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] From 85b3024e8aff1c79dfe94a52cbf01d42dcfcfb60 Mon Sep 17 00:00:00 2001 From: Katie Date: Tue, 5 Jan 2021 19:43:06 -0800 Subject: [PATCH 2/2] implemented methods --- lib/max_subarray.rb | 25 ++++++++++++++++++++----- lib/newman_conway.rb | 26 ++++++++++++++++++++++---- test/max_sub_array_test.rb | 2 +- 3 files changed, 43 insertions(+), 10 deletions(-) diff --git a/lib/max_subarray.rb b/lib/max_subarray.rb index 5204edb..3aff68a 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.empty? + max_so_far = nums[0] + max_ending_here = nums[0] + + nums.each_with_index do |num, index| + if index != 0 + max_ending_here += num + if(max_ending_here < num) + max_ending_here = num + end + + if(max_so_far < max_ending_here) + max_so_far = max_ending_here + end + end + end + + return max_so_far end diff --git a/lib/newman_conway.rb b/lib/newman_conway.rb index 4c985cd..1c95aee 100644 --- a/lib/newman_conway.rb +++ b/lib/newman_conway.rb @@ -1,7 +1,25 @@ -# Time complexity: ? -# Space Complexity: ? +# Time complexity: O(n) +# Space Complexity: O(n) def newman_conway(num) - raise NotImplementedError, "newman_conway isn't implemented" -end \ No newline at end of file + if(num < 1) + raise ArgumentError + elsif(num == 1) + return "1" + elsif(num == 2) + return "1 1" + end + + array = [0, 1, 1] + while array.length <= num + array.push(array[array[array.length - 1]] + array[array.length - array[array.length - 1]]) + end + + return array[1..array.length].join(" ") +end + +# P(1) = 1 +# P(2) = 1 +# for all n > 2 +# P(n) = P(P(n - 1)) + P(n - P(n - 1)) \ 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]