Fire - Gessica Mohr

lib/max_subarray.rb

@@ -1,8 +1,25 @@
 
-# Time Complexity: ?
-# Space Complexity: ?
+# Time Complexity: O(n)
+# Space Complexity: O(1)
 def max_sub_array(nums)
-    return 0 if nums == nil
+    return nil if nums.empty?
 
-    raise NotImplementedError, "Method not implemented yet!"
-end
+    # raise NotImplementedError, "Method not implemented yet!"
+    max_so_far = nums[0]
+    current_max = 0
+
+    nums.each do |num|
+
+        current_max += num
+
+        if max_so_far < current_max
+            max_so_far = current_max
+        elsif current_max < 0
+            current_max = 0
+        end
+
+    end
+
+    return max_so_far   
+
+end

lib/newman_conway.rb

@@ -1,7 +1,30 @@
 
 
-# Time complexity: ?
-# Space Complexity: ?
+# Time complexity: O(n)
+# Space Complexity: O(n)
 def newman_conway(num)
-  raise NotImplementedError, "newman_conway isn't implemented"
-end
+  # raise NotImplementedError, "newman_conway isn't implemented"
+  raise ArgumentError if num < 1
+
+  return "1" if num == 1
+  return "1 1" if num == 2
+
+  sequence = [0, 1, 1]
+
+  i = 3
+
+  (3..num).each do |i|
+    sequence.push(sequence[sequence[i -1]] + sequence[i - sequence[i - 1]])
+    i += 1
+  end
+
+  sequence.shift
+  return sequence.join(' ')
+
+end
+
+
+# P(1) = 1
+# P(2) = 1
+# for all n > 2
+# P(n) = P(P(n - 1)) + P(n - P(n - 1))

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]