Kirsten

lib/max_subarray.rb

@@ -1,8 +1,17 @@
 
-# Time Complexity: ?
-# Space Complexity: ?
+# Time Complexity: O(n) where n is the number of items in the array
+# 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
+  return nil if nums.length == 0
+  max_sum = nums[0]
+  sum = 0
+
+  nums.length.times do |i|
+    sum = [nums[i], sum + nums[i]].max
+    if sum > max_sum
+      max_sum = sum
+    end
+  end
+  return max_sum
 end

lib/newman_conway.rb

@@ -1,7 +1,32 @@
 
 
-# Time complexity: ?
-# Space Complexity: ?
+# Time complexity: O(n), where n is the input number
+# Space Complexity: O(n), where n is the input number
 def newman_conway(num)
-  raise NotImplementedError, "newman_conway isn't implemented"
+    raise ArgumentError, "input must be greater than 0" if num < 1
+
+  storage_hash = {
+    1 => 1,
+    2 => 1
+  }
+
+  results = []
+  if num <= 2
+    num.times do |i|
+      results.push(storage_hash[i + 1])
+    end
+  else
+    2.times do |i|
+      results.push(storage_hash[i + 1])
+    end
+  end
+  n = 3
+  while n <= num
+    prev = storage_hash[n - 1]
+    storage_hash[n] = storage_hash[prev] + storage_hash[n - prev]
+    results.push "#{storage_hash[n]}"
+    n += 1
+  end
+
+  return results.join(" ")
 end

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]