From 425cd8b54f5f88fc6cbf1a82aceac62a64bbaf06 Mon Sep 17 00:00:00 2001
From: Ga-Young Jin <gyjinn@gmail.com>
Date: Sat, 28 Mar 2020 23:56:21 -0700
Subject: [PATCH 1/2] completed newman conway

---
 lib/newman_conway.rb       | 28 ++++++++++++++----
 test/newman_conway_test.rb | 58 +++++++++++++++++++-------------------
 2 files changed, 51 insertions(+), 35 deletions(-)

diff --git a/lib/newman_conway.rb b/lib/newman_conway.rb
index 4c985cd..16016b8 100644
--- a/lib/newman_conway.rb
+++ b/lib/newman_conway.rb
@@ -1,7 +1,23 @@
-
-
-# Time complexity: ?
-# Space Complexity: ?
+# Time complexity: O(n * num) ?
+# Space Complexity: O(num) ?
 def newman_conway(num)
-  raise NotImplementedError, "newman_conway isn't implemented"
-end
\ No newline at end of file
+  newman_conway_helper([0, 1, 1], 3, num)
+end
+
+def newman_conway_helper(p, current, n)
+  if n <= 0
+    raise ArgumentError, "Input must be greater than 0."
+  end
+  
+  return "1" if n == 1
+  return "1 1" if n == 2
+  
+  if current > n 
+    p.shift # S: O(n)?  T: O(n)?
+    return p.join(" ")
+  end
+  
+  p << p[p[current - 1]] + p[current - p[current - 1]]
+  
+  return newman_conway_helper(p, current + 1, n) # T: O(num) calls this recursively about num number of times
+end
diff --git a/test/newman_conway_test.rb b/test/newman_conway_test.rb
index 537d376..c1661a6 100644
--- a/test/newman_conway_test.rb
+++ b/test/newman_conway_test.rb
@@ -4,51 +4,51 @@
   it "works with 13" do
     # Arrange
     input = 13
-
+    
     # Act
     answer = newman_conway(input)
-
+    
     # Assert
     expect(answer).must_equal "1 1 2 2 3 4 4 4 5 6 7 7 8"
   end
-
+  
   it "works with 20" do
     # Arrange
     input = 20
-
+    
     # Act
     answer = newman_conway(input)
-
+    
     # Assert
     expect(answer).must_equal "1 1 2 2 3 4 4 4 5 6 7 7 8 8 8 8 9 10 11 12"
   end
-
+  
   it "works with base cases" do
-        # Arrange
-        input = 0
-
-        # Act-Assert
-        expect {
-          newman_conway(input)
-        }.must_raise ArgumentError
+    # Arrange
+    input = 0
     
-
-        # Arrange
-        input = 1
-
-        # Act
-        answer = newman_conway(input)
+    # Act-Assert
+    expect {
+      newman_conway(input)
+    }.must_raise ArgumentError
     
-        # Assert
-        expect(answer).must_equal "1"
-
-        # Arrange
-        input = 2
-
-        # Act
-        answer = newman_conway(input)
     
-        # Assert
-        expect(answer).must_equal "1 1"        
+    # 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

From 3937c4ed5d48e6344d37092a86f9730e9478ec6f Mon Sep 17 00:00:00 2001
From: Ga-Young Jin <gyjinn@gmail.com>
Date: Thu, 23 Apr 2020 23:25:46 -0700
Subject: [PATCH 2/2] completed max_subarray

---
 lib/max_subarray.rb        | 21 +++++++++++++---
 test/max_sub_array_test.rb | 50 +++++++++++++++++++-------------------
 2 files changed, 43 insertions(+), 28 deletions(-)

diff --git a/lib/max_subarray.rb b/lib/max_subarray.rb
index 5204edb..4b7d414 100644
--- a/lib/max_subarray.rb
+++ b/lib/max_subarray.rb
@@ -1,8 +1,23 @@
 
-# Time Complexity: ?
-# Space Complexity: ?
+# Time Complexity: O(nums)
+# Space Complexity: O(1)
 def max_sub_array(nums)
     return 0 if nums == nil
     
-    raise NotImplementedError, "Method not implemented yet!"
+    max_so_far = nums[0]
+    max_ending_here = nums[0]
+    
+    counter = 1
+    until counter > nums.length - 1 # T: O(nums)
+        max_ending_here = max_ending_here + nums[counter]
+        if max_ending_here < nums[counter]
+            max_ending_here = nums[counter]
+        end
+        
+        if max_ending_here > max_so_far
+            max_so_far = max_ending_here
+        end
+        counter += 1
+    end
+    return max_so_far
 end
diff --git a/test/max_sub_array_test.rb b/test/max_sub_array_test.rb
index 3253cdf..5f930ef 100644
--- a/test/max_sub_array_test.rb
+++ b/test/max_sub_array_test.rb
@@ -1,70 +1,70 @@
 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]
-
+    
     # Act
     answer = max_sub_array(input)
-
+    
     # Assert
     expect(answer).must_equal 6
   end
-
+  
   it "will work with a totally negative array" do
     # Arrange
     input = [-3, -4, -5, -6, -7]
-
+    
     # Act
     answer = max_sub_array(input)
-
+    
     # Assert
     expect(answer).must_equal(-3)
   end
-
+  
   it "will work with a totally negative array with the largest element at the rear" do
     # Arrange
     input = [ -4, -5, -6, -7, -3]
-
+    
     # Act
     answer = max_sub_array(input)
-
+    
     # Assert
     expect(answer).must_equal(-3)
   end
-
+  
   it "will work with a 1-element array" do
     # Arrange
     input = [3]
-
+    
     # Act
     answer = max_sub_array(input)
-
+    
     # Assert
     expect(answer).must_equal 3
   end
-
+  
   it "will return nil for an empty array" do
-   # Arrange
-   input = []
-
-   # Act
-   answer = max_sub_array(input)
-
-   # Assert
-   expect(answer).must_be_nil
+    # Arrange
+    input = []
+    
+    # Act
+    answer = max_sub_array(input)
+    
+    # Assert
+    expect(answer).must_be_nil
   end
-
+  
   it "will work for [50, -50, 50]" do
     # Arrange
     input = [50, -50, 50]
-
+    
     # Act
     answer = max_sub_array(input)
-
+    
     # Assert
     expect(answer).must_equal 50
   end
-
+  
 end
\ No newline at end of file