diff --git a/lib/max_subarray.rb b/lib/max_subarray.rb index 5204edb..f5b3fe9 100644 --- a/lib/max_subarray.rb +++ b/lib/max_subarray.rb @@ -1,8 +1,24 @@ -# 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.max + if max_so_far < 0 + return max_so_far + end + max_ending_here = 0 + + nums.each do |num| + max_ending_here = max_ending_here + num + + if max_ending_here < 0 + max_ending_here = 0 + end + if max_so_far < max_ending_here + max_so_far = max_ending_here + end + end + return max_so_far end diff --git a/lib/newman_conway.rb b/lib/newman_conway.rb index 4c985cd..566175f 100644 --- a/lib/newman_conway.rb +++ b/lib/newman_conway.rb @@ -1,7 +1,20 @@ -# Time complexity: ? -# Space Complexity: ? -def newman_conway(num) - raise NotImplementedError, "newman_conway isn't implemented" -end \ No newline at end of file +# Time complexity: O(n) +# Space Complexity: O(n) + + +def newman_conway(nums) + result = Array.new() + raise ArgumentError if nums == 0 + return "1" if nums == 1 + result[1] = 1 + result[2] = 1 + if nums > 2 + (3..nums).each do |num| + result[num] = result[result[num - 1]] + result[num - result[num - 1]] + end + end + result.delete_at(0) + return result.join(" ") +end 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]