diff --git a/lib/max_subarray.py b/lib/max_subarray.py index 4e892e0..994ec56 100644 --- a/lib/max_subarray.py +++ b/lib/max_subarray.py @@ -2,11 +2,23 @@ def max_sub_array(nums): """ Returns the max subarray of the given list of numbers. Returns 0 if nums is None or an empty list. - Time Complexity: ? - Space Complexity: ? + Time Complexity: O(n) + Space Complexity: O(1) """ - if nums == None: + if not nums: + return 0 + if not len(nums): return 0 - if len(nums) == 0: - return 0 - pass + + max_so_far = 0 + max_ending_here = 0 + + for num in nums: + max_ending_here = max_ending_here + num + if max_ending_here < 0: + max_ending_here = 0 + if max_so_far < max_ending_here: + max_so_far = max_ending_here + + return max(nums) if max_so_far == 0 else max_so_far + diff --git a/lib/newman_conway.py b/lib/newman_conway.py index 70a3353..aa924c5 100644 --- a/lib/newman_conway.py +++ b/lib/newman_conway.py @@ -1,10 +1,15 @@ - - -# Time complexity: ? -# Space Complexity: ? def newman_conway(num): """ Returns a list of the Newman Conway numbers for the given value. - Time Complexity: ? - Space Complexity: ? + Time Complexity: O(n) + Space Complexity: O(n) """ - pass + if num <= 0: + raise ValueError + elif num == 1: + return '1' + else: + memo = [0, 1, 1] + for i in range(3, num+1): + next_num = memo[memo[-1]] + memo[i-memo[i-1]] + memo.append(next_num) + return ' '.join([str(i) for i in memo if i])