diff --git a/lib/max_subarray.rb b/lib/max_subarray.rb index 5204edb..be28b72 100644 --- a/lib/max_subarray.rb +++ b/lib/max_subarray.rb @@ -2,7 +2,22 @@ # Time Complexity: ? # Space Complexity: ? def max_sub_array(nums) - return 0 if nums == nil - - raise NotImplementedError, "Method not implemented yet!" + return 0 if nums == nil + return nil if nums.empty? + + max_so_far = max_ending_here = nums[0] + + nums[1..-1].each do |num| + if num > max_ending_here + num + max_ending_here = num + else + max_ending_here += num + 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..01ea003 100644 --- a/lib/newman_conway.rb +++ b/lib/newman_conway.rb @@ -1,7 +1,21 @@ -# 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 + + storage = [] + + i = 1 + while i <= num + if i < 3 + storage[i] = 1 + else + storage[i] = storage[storage[i - 1]] + storage[i - storage[i - 1]] + end + i += 1 + end + + return storage.join(" ")[1..-1] # fencepost slice 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]