diff --git a/lib/max_subarray.rb b/lib/max_subarray.rb index 5204edb..eb31396 100644 --- a/lib/max_subarray.rb +++ b/lib/max_subarray.rb @@ -1,8 +1,27 @@ +# Time Complexity: O(n) +# Space Complexity: O(1) -# Time Complexity: ? -# Space Complexity: ? def max_sub_array(nums) return 0 if nums == nil + return nil if nums == [] - raise NotImplementedError, "Method not implemented yet!" + curr_max = nums[0] + max_so_far = nums[0] + + i = 1 + until i == nums.length + if curr_max + nums[i] < nums[i] + curr_max = nums[i] + else + curr_max += nums[i] + end + + if curr_max > max_so_far + max_so_far = curr_max + end + + i += 1 + end + + return max_so_far end diff --git a/lib/newman_conway.rb b/lib/newman_conway.rb index 4c985cd..9ca731f 100644 --- a/lib/newman_conway.rb +++ b/lib/newman_conway.rb @@ -1,7 +1,18 @@ +# Time complexity: O(n) +# Space Complexity: O(n) - -# Time complexity: ? -# Space Complexity: ? def newman_conway(num) - raise NotImplementedError, "newman_conway isn't implemented" -end \ No newline at end of file + raise ArgumentError if num < 1 + return "1" if num == 1 + return "1 1" if num == 2 + + s = [0, 1, 1] + result = "1 1" + + for i in 3..num + s[i] = s[s[i - 1]] + s[i - s[i - 1]] + result << " #{s[i]}" + end + + return result +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]