diff --git a/lib/max_subarray.rb b/lib/max_subarray.rb index 5204edb..5e037a3 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(n) def max_sub_array(nums) - return 0 if nums == nil - - raise NotImplementedError, "Method not implemented yet!" + return nil if nums.empty? +# Initialize: + max_so_far = nums[0] + max_ending_here = 0 + +# Loop for each element of the array +nums.each do |num| + max_ending_here = max_ending_here + num + if max_so_far < max_ending_here + max_so_far = max_ending_here + end + if max_ending_here < 0 + max_ending_here = 0 + end + end + return max_so_far end diff --git a/lib/newman_conway.rb b/lib/newman_conway.rb index 4c985cd..2723ea9 100644 --- a/lib/newman_conway.rb +++ b/lib/newman_conway.rb @@ -1,7 +1,16 @@ - -# Time complexity: ? -# Space Complexity: ? +# Time complexity: O(n) +# Space Complexity: O(n)2 def newman_conway(num) - raise NotImplementedError, "newman_conway isn't implemented" -end \ No newline at end of file + raise ArgumentError if num == 0 + return "1" if num == 1 + arr = [0, 1, 1] + + current_index = 3 # why index?? + while num >= current_index + arr.push(arr[arr[current_index - 1]] + arr[current_index - arr[current_index - 1]]) + current_index += 1 + end + + return arr[1..arr.length].join(' ') +end diff --git a/test/max_sub_array_test.rb b/test/max_sub_array_test.rb index 3253cdf..ac403f9 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] @@ -46,14 +46,14 @@ end it "will return nil for an empty array" do - # Arrange - input = [] + # Arrange + input = [] - # Act - answer = max_sub_array(input) + # Act + answer = max_sub_array(input) - # Assert - expect(answer).must_be_nil + # Assert + expect(answer).must_be_nil end it "will work for [50, -50, 50]" do diff --git a/test/newman_conway_test.rb b/test/newman_conway_test.rb index 537d376..ce089b0 100644 --- a/test/newman_conway_test.rb +++ b/test/newman_conway_test.rb @@ -24,31 +24,31 @@ end it "works with base cases" do - # Arrange - input = 0 - - # Act-Assert - expect { - newman_conway(input) - }.must_raise ArgumentError - - - # Arrange - input = 1 - - # Act - answer = newman_conway(input) - - # Assert - expect(answer).must_equal "1" - - # Arrange - input = 2 - - # Act - answer = newman_conway(input) - - # Assert - expect(answer).must_equal "1 1" + # Arrange + input = 0 + + # Act-Assert + expect { + newman_conway(input) + }.must_raise ArgumentError + + + # Arrange + input = 1 + + # Act + answer = newman_conway(input) + + # Assert + expect(answer).must_equal "1" + + # Arrange + input = 2 + + # Act + answer = newman_conway(input) + + # Assert + expect(answer).must_equal "1 1" end end