diff --git a/lib/max_subarray.rb b/lib/max_subarray.rb index 5204edb..b9f7f83 100644 --- a/lib/max_subarray.rb +++ b/lib/max_subarray.rb @@ -1,8 +1,16 @@ +# Reference: https://medium.com/@rsinghal757/kadanes-algorithm-dynamic-programming-how-and-why-does-it-work-3fd8849ed73d -# Time Complexity: ? -# Space Complexity: ? +# Time Complexity: O(n), where n is the length of nums +# Space Complexity: O(1) def max_sub_array(nums) - return 0 if nums == nil - - raise NotImplementedError, "Method not implemented yet!" + max = nums[0] + local_max = 0 + + nums.each do |n| + local_max += n + max = local_max if max < local_max + local_max = 0 if local_max < 0 + end + + return max end diff --git a/lib/newman_conway.rb b/lib/newman_conway.rb index 4c985cd..d52c243 100644 --- a/lib/newman_conway.rb +++ b/lib/newman_conway.rb @@ -1,7 +1,21 @@ +# Reference: https://www.geeksforgeeks.org/print-n-terms-newman-conway-sequence/ - -# Time complexity: ? -# Space Complexity: ? +# Time complexity: O(n) if num is greater than 2, where n is num +# Space Complexity: O(n) def newman_conway(num) - raise NotImplementedError, "newman_conway isn't implemented" -end \ No newline at end of file + raise ArgumentError if num < 1 + sequence = [0, 1, 1] + output = "" + output += "#{sequence[1]}" + " " + output += "#{sequence[2]}" + " " if num > 1 + + i = 3 + while i <= num + sequence << sequence[sequence[i - 1]] + sequence[i - sequence[i - 1]] + output += "#{sequence[i]}" + " " + i += 1 + end + + return output.chomp(" ") +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]