Time - Hannah T

Gemfile

@@ -1,10 +1,9 @@
 # frozen_string_literal: true
 source "https://rubygems.org"
 
-gem 'rake'
-gem 'minitest'
-gem 'minitest-spec'
-gem 'minitest-reporters'
+gem "rake"
+gem "minitest"
+gem "minitest-spec"
+gem "minitest-reporters"
 gem "pry"
-gem 'minitest-skip'
-
+gem "minitest-skip"

Rakefile

@@ -1,9 +1,9 @@
-require 'rake/testtask'
+require "rake/testtask"
 
 Rake::TestTask.new do |t|
   t.libs = ["lib"]
   t.warning = true
-  t.test_files = FileList['test/*_test.rb']
+  t.test_files = FileList["test/*_test.rb"]
 end
 
 task default: :test

lib/max_subarray.rb

@@ -1,8 +1,17 @@
-
-# Time Complexity: ?
-# Space Complexity: ?
+# Time Complexity: O(n)
+# Space Complexity: O(1)
 def max_sub_array(nums)
-    return 0 if nums == nil
-
-    raise NotImplementedError, "Method not implemented yet!"
+  max_so_far = max_ending_here = nums[0]
+  for i in 1..nums.length - 1
+    # puts nums[i]
+    puts max_ending_here
+    max_ending_here = max_ending_here + nums[i]
+    if max_ending_here < nums[i]
+      max_ending_here = nums[i]
+    end
+    if max_so_far < max_ending_here
+      max_so_far = max_ending_here
+    end
+  end
+  return max_so_far
 end

lib/newman_conway.rb

@@ -1,7 +1,37 @@
+# Time complexity: O(n)
+# Space Complexity: O(n)
 
-
-# Time complexity: ?
-# Space Complexity: ?
 def newman_conway(num)
-  raise NotImplementedError, "newman_conway isn't implemented"
-end
+  raise ArgumentError if num <= 0
+  return "1" if num == 1
+
+  cached_array = [1, 1, 1]
+
+  for i in 3..num
+    current = cached_array[cached_array[i - 1]] + cached_array[i - (cached_array[i - 1])]
+    cached_array[i] = current
+  end
+  cached_array.delete_at(0)
+  return cached_array.join(" ")
+end
+
+
+
+
+
+
+# def newman_conway(num)
+#   raise ArgumentError if num <= 0
+#   return "1" if num  == 1
+
+#   cached_array = [0, 1, 1]
+#   i = 3
+#   until i >= num + 1
+#     current = cached_array[cached_array[i - 1]] + cached_array[i - (cached_array[i - 1])]
+
+#     cached_array[i] = current
+#     i += 1
+#   end
+#   cached_array.delete_at(0)
+#   return cached_array.join(' ')
+# end

test/max_sub_array_test.rb

@@ -1,9 +1,9 @@
 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]
+    input = [-2, 1, -3, 4, -1, 2, 1, -5, 4]
 
     # Act
     answer = max_sub_array(input)
@@ -25,7 +25,7 @@
 
   it "will work with a totally negative array with the largest element at the rear" do
     # Arrange
-    input = [ -4, -5, -6, -7, -3]
+    input = [-4, -5, -6, -7, -3]
 
     # Act
     answer = max_sub_array(input)
@@ -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
@@ -66,5 +66,4 @@
     # Assert
     expect(answer).must_equal 50
   end
-
-end
+end

test/newman_conway_test.rb

@@ -24,31 +24,30 @@
   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

test/test_helper.rb

@@ -1,10 +1,9 @@
-
-require 'minitest'
-require 'minitest/autorun'
-require 'minitest/reporters'
+require "minitest"
+require "minitest/autorun"
+require "minitest/reporters"
 require "minitest/skip_dsl"
 
 Minitest::Reporters.use! Minitest::Reporters::SpecReporter.new
 
 require_relative "../lib/newman_conway"
-require_relative "../lib/max_subarray"
+require_relative "../lib/max_subarray"