diff --git a/lib/max_subarray.rb b/lib/max_subarray.rb index 5204edb..1a705bb 100644 --- a/lib/max_subarray.rb +++ b/lib/max_subarray.rb @@ -1,8 +1,18 @@ -# Time Complexity: ? -# Space Complexity: ? -def max_sub_array(nums) - return 0 if nums == nil - - raise NotImplementedError, "Method not implemented yet!" +# Time Complexity: O(n) because the each loop will iterate through each item in the array +# Space Complexity: O(1) there are no additional data structures or recursive calls to add to space complexity +def max_sub_array(array) + return nil if array.empty? + return array.first if array.length == 1 + + max_so_far = array[0] + max_ending_here = array[0] + + (1..array.length - 1).each do |i| + max_ending_here = [array[i], max_ending_here + array[i]].max + max_so_far = [max_ending_here, max_so_far].max + end + + return max_so_far end + \ No newline at end of file diff --git a/lib/newman_conway.rb b/lib/newman_conway.rb index 4c985cd..fbaff2a 100644 --- a/lib/newman_conway.rb +++ b/lib/newman_conway.rb @@ -1,7 +1,18 @@ +# Time complexity: O(n) because the each loop is run n times +# Space Complexity: O(n) because there is an additional array solutions that varies linearly with size of n +def newman_conway(terms) + raise ArgumentError if terms < 1 + solutions = [nil] -# Time complexity: ? -# Space Complexity: ? -def newman_conway(num) - raise NotImplementedError, "newman_conway isn't implemented" + (1..terms).each do |n| + if n < 3 + solutions << 1 + else + solutions << (solutions[solutions[n - 1]] + solutions[n - solutions[n - 1]]) + end + end + + solutions.shift + return solutions.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]