diff --git a/lib/max_subarray.rb b/lib/max_subarray.rb index 5204edb..4ff07a5 100644 --- a/lib/max_subarray.rb +++ b/lib/max_subarray.rb @@ -1,8 +1,33 @@ -# 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 0 if nums == nil + # raise NotImplementedError, "Method not implemented yet!" + max_so_far = nums[0] + max_ending_here = 0 + + nums.each do |num| + max_ending_here = max_ending_here + num + if max_ending_here < num + 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 + +# Initialize: +# max_so_far = 0 +# max_ending_here = 0 + +# Loop for each element of the array +# (a) max_ending_here = max_ending_here + a[i] +# (b) if(max_ending_here < 0) +# max_ending_here = 0 +# (c) if(max_so_far < max_ending_here) +# max_so_far = max_ending_here +# return max_so_far diff --git a/lib/newman_conway.rb b/lib/newman_conway.rb index 4c985cd..23ac6dc 100644 --- a/lib/newman_conway.rb +++ b/lib/newman_conway.rb @@ -1,7 +1,23 @@ +# Time complexity: o(n) +# Space Complexity: o(n) -# Time complexity: ? -# Space Complexity: ? def newman_conway(num) - raise NotImplementedError, "newman_conway isn't implemented" + # raise NotImplementedError, "newman_conway isn't implemented" + raise ArgumentError if num < 1 + return "1" if num == 1 + return "1 1" if num == 2 + + newman_conway = [0, 1, 1] + sequence = "1 1" + + i = 3 + + while i <= num + #p(i) = p(p(i-1)) + p(i - p(i - 1)) + newman_conway[i] = newman_conway[newman_conway[i - 1]] + newman_conway [i - newman_conway[i - 1]] + sequence += " #{newman_conway[i]}" + i += 1 + end + return sequence 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]