diff --git a/lib/max_subarray.rb b/lib/max_subarray.rb index 5204edb..52ed279 100644 --- a/lib/max_subarray.rb +++ b/lib/max_subarray.rb @@ -1,8 +1,23 @@ -# 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 nums.inject(:+) if nums.length <= 3 + + max_so_far = nums[0] + max_ending_here = nums[0] + + nums.each do |num| + if max_ending_here < num + max_ending_here = num + elsif num < max_ending_here + 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..dfb3adb 100644 --- a/lib/newman_conway.rb +++ b/lib/newman_conway.rb @@ -1,7 +1,22 @@ +# Time complexity: O(n) +# Space Complexity: O(n) +def newman_conway(num) + raise ArgumentError if num == 0 + array = [num, 0] + count = 1 + + until count > num + if count == 1 || count == 2 + array[count] = 1 + else + array[count] = array[array[count - 1]] + array[count - array[count - 1]] + end + + count += 1 + end -# Time complexity: ? -# Space Complexity: ? -def newman_conway(num) - raise NotImplementedError, "newman_conway isn't implemented" + p array[1..(array.length - 1)].join(' ') + + array[1..(array.length - 1)].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]