diff --git a/lib/max_subarray.rb b/lib/max_subarray.rb index 5204edb..ab36051 100644 --- a/lib/max_subarray.rb +++ b/lib/max_subarray.rb @@ -1,8 +1,21 @@ - -# 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!" + result = nil + if nums == nil + result = 0 + elsif nums.length > 0 + max_so_far = 0 + max_ending_here = 0 + largest_element = nums[0] + nums.each do |element| + max_ending_here = max_ending_here + element + + max_ending_here = 0 if max_ending_here < 0 + max_so_far = max_ending_here if max_so_far < max_ending_here + largest_element = element if element > largest_element + end + result = (largest_element < 0) ? largest_element : max_so_far + end + return result end diff --git a/lib/newman_conway.rb b/lib/newman_conway.rb index 4c985cd..8e22eec 100644 --- a/lib/newman_conway.rb +++ b/lib/newman_conway.rb @@ -1,7 +1,15 @@ - - -# Time complexity: ? -# Space Complexity: ? +# Time complexity: O(n) +# Space Complexity: O(n) def newman_conway(num) - raise NotImplementedError, "newman_conway isn't implemented" + raise ArgumentError if num < 1 + output = Array.new() + num.times do |i| + if i < 2 + output << 1 + else + previous = output[i - 1] + output << output[previous - 1] + output[i - previous] + end + end + return output.join(" ") 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]