Fire - Blaine

lib/max_subarray.rb

@@ -1,8 +1,21 @@
 
-# Time Complexity: ?
-# Space Complexity: ?
+# Time Complexity: O(n)
+# Space Complexity: O(n)
 def max_sub_array(nums)
-    return 0 if nums == nil
-
-    raise NotImplementedError, "Method not implemented yet!"
+    return nil if nums.empty?
+#     Initialize:
+    max_so_far = nums[0]
+    max_ending_here = 0
+
+# Loop for each element of the array
+nums.each do |num|
+    max_ending_here = max_ending_here + num
+        if max_so_far < max_ending_here
+            max_so_far = max_ending_here
+        end
+        if max_ending_here < 0
+            max_ending_here = 0
+        end
+    end
+    return max_so_far
 end

lib/newman_conway.rb

@@ -1,7 +1,16 @@
 
-
-# Time complexity: ?
-# Space Complexity: ?
+# Time complexity: O(n)
+# Space Complexity: O(n)2
 def newman_conway(num)
-  raise NotImplementedError, "newman_conway isn't implemented"
-end
+  raise ArgumentError if num == 0
+  return "1" if num == 1
+  arr = [0, 1, 1]
+
+  current_index = 3 # why index?? 
+  while num >= current_index
+    arr.push(arr[arr[current_index - 1]] + arr[current_index - arr[current_index - 1]])
+    current_index += 1
+  end
+
+  return arr[1..arr.length].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]
@@ -46,14 +46,14 @@
   end
 
   it "will return nil for an empty array" do
-   # Arrange
-   input = []
+    # Arrange
+    input = []
 
-   # Act
-   answer = max_sub_array(input)
+    # Act
+    answer = max_sub_array(input)
 
-   # Assert
-   expect(answer).must_be_nil
+    # Assert
+    expect(answer).must_be_nil
   end
 
   it "will work for [50, -50, 50]" do

test/newman_conway_test.rb

@@ -24,31 +24,31 @@
   end
 
   it "works with base cases" do
-        # Arrange
-        input = 0
-
-        # Act-Assert
-        expect {
-          newman_conway(input)
-        }.must_raise ArgumentError
-    
-
-        # Arrange
-        input = 1
-
-        # Act
-        answer = newman_conway(input)
-    
-        # Assert
-        expect(answer).must_equal "1"
-
-        # Arrange
-        input = 2
-
-        # Act
-        answer = newman_conway(input)
-    
-        # Assert
-        expect(answer).must_equal "1 1"        
+    # Arrange
+    input = 0
+
+    # Act-Assert
+    expect {
+      newman_conway(input)
+    }.must_raise ArgumentError
+
+
+    # Arrange
+    input = 1
+
+    # Act
+    answer = newman_conway(input)
+
+    # Assert
+    expect(answer).must_equal "1"
+
+    # Arrange
+    input = 2
+
+    # Act
+    answer = newman_conway(input)
+
+    # Assert
+    expect(answer).must_equal "1 1"        
   end
 end