From ab668c1e481cf4fd15e7a1ceb6d554c323f8b179 Mon Sep 17 00:00:00 2001
From: Darrell Abrau <darrellabrau@gmail.com>
Date: Fri, 29 Aug 2014 04:05:16 -0500
Subject: [PATCH 1/2] completed find sum 3

---
 array_problems/arrays.rb | 35 ++++++++++++++++++++++++++++++++
 set1/set1.rb             | 44 +++++++++++++++++++++++++++++++++++++++-
 set1/spec/set1_spec.rb   | 20 +++++++++---------
 3 files changed, 88 insertions(+), 11 deletions(-)

diff --git a/array_problems/arrays.rb b/array_problems/arrays.rb
index 7a4a2cc..35ce1e2 100644
--- a/array_problems/arrays.rb
+++ b/array_problems/arrays.rb
@@ -2,12 +2,47 @@
 require 'pry-byebug'
 
 module ArrayUtil
+
+
+
   def self.max(array)
+
+  	x = array[0]
+
+  	array.each_with_index do |item, index| 
+  		if (array[index] > x)
+  			x = array[index]
+  		end
+  	end
+		x
   end
 
+
+
+
+
+
+
+
   def self.middle_element(array)
+  
+  	if array.length % 2 == 1
+  		return array[array.length]
+  	# else
+  	# 	return [array[z], array[(z+1)]]
+  	end
   end
 
+
+
+
+
+
+
+
+
+
   def self.sum_arrays(array1, array2)
+
   end
 end
diff --git a/set1/set1.rb b/set1/set1.rb
index 0ca2970..37102ff 100644
--- a/set1/set1.rb
+++ b/set1/set1.rb
@@ -1,10 +1,52 @@
 module Set1
+
+	#O(n)
   def self.swap_small(array)
-  end
+  	first_element=array[0]
+
+  	smallest_value = array[0]
+  	smallest_index = 0
 
+  	array.each_with_index do |item, index|
+  		if array[index] < smallest_value
+  			smallest_value = array[index]
+  			smallest_index = index
+  		end
+  	end
+
+  	array.insert(0, smallest_value)
+  	array.delete_at(1)
+  	array.delete_at(smallest_index)
+  	array.insert(smallest_index, first_element)
+  end
+  #O(n^2)
   def self.find_sum_2(array, sum = 0)
+  	
+
+  	array.each do |x| 
+  		 array.each do |a|
+  		 	if x + a == 0
+  		 		return true
+  		 	end
+  		end
+  	end
+
+  	return false
+
   end
 
+  #O(n^3)
   def self.find_sum_3(array)
+  	array.each do |a|
+  		array.each do |b|
+  			array.each do |c|
+  				if a + b + c == 0
+  					return true
+  				end
+  			end
+  		end
+  	end
+
+  	return false
   end
 end
diff --git a/set1/spec/set1_spec.rb b/set1/spec/set1_spec.rb
index 4d90f4e..1284488 100644
--- a/set1/spec/set1_spec.rb
+++ b/set1/spec/set1_spec.rb
@@ -24,48 +24,48 @@
   end
 
   describe ".find_sum_2" do
-    xit "should return false for an empty array" do
+    it "should return false for an empty array" do
       expect(Set1.find_sum_2([])).to eq(false)
     end
 
-    xit "should return true for an array with just the number 0" do
+    it "should return true for an array with just the number 0" do
       expect(Set1.find_sum_2([0])).to eq(true)
     end
 
-    xit "should return true for an array with the number 0 in it" do
+    it "should return true for an array with the number 0 in it" do
       expect(Set1.find_sum_2([5, 2, 0, -100])).to eq(true)
     end
 
-    xit "should return true if a number and it's negative are in the arrray" do
+    it "should return true if a number and it's negative are in the arrray" do
       expect(Set1.find_sum_2([5, 20, -5, 100])).to eq(true)
       expect(Set1.find_sum_2([5, 20, -3, 100, -20, 2])).to eq(true)
     end
 
-    xit "should return false if none of the numbers add to 0" do
+    it "should return false if none of the numbers add to 0" do
       expect(Set1.find_sum_2([5, 6, 7, 8, -1, -2, -3, -4])).to eq(false)
     end
   end
 
   describe ".find_sum_3" do
-    xit "should return false for an empty array" do
+    it "should return false for an empty array" do
       expect(Set1.find_sum_3([])).to eq(false)
     end
 
-    xit "should return true for an array with just the number 0" do
+    it "should return true for an array with just the number 0" do
       expect(Set1.find_sum_3([0])).to eq(true)
     end
 
-    xit "should return true for an array with the number 0 in it" do
+    it "should return true for an array with the number 0 in it" do
       expect(Set1.find_sum_3([5, 2, 0, -100])).to eq(true)
     end
 
-    xit "should return true if 3 numbers in the array add to 0" do
+    it "should return true if 3 numbers in the array add to 0" do
       expect(Set1.find_sum_3([10, 2, 100, -200, -102, 5])).to eq(true)
       expect(Set1.find_sum_3([10, -51, 100, -201, 102, 5])).to eq(true)
       expect(Set1.find_sum_3([10, 51, 100, -201, -102, 5])).to eq(true) # 51, 51, -102
     end
 
-    xit "should return false if no 3 numbers in the array add to 0" do
+    it "should return false if no 3 numbers in the array add to 0" do
       expect(Set1.find_sum_3([10, 51, 100, 201, 102, 5])).to eq(false)
     end
   end

From a95f6f67dac72b7cf58e7c13bcf3be86a5487fb6 Mon Sep 17 00:00:00 2001
From: Darrell Abrau <darrellabrau@gmail.com>
Date: Fri, 29 Aug 2014 05:29:48 -0500
Subject: [PATCH 2/2] initial commit of arrays exercise

---
 array_problems/arrays.rb | 35 ++++++++++++++++++++++++++---------
 1 file changed, 26 insertions(+), 9 deletions(-)

diff --git a/array_problems/arrays.rb b/array_problems/arrays.rb
index 35ce1e2..728dd46 100644
--- a/array_problems/arrays.rb
+++ b/array_problems/arrays.rb
@@ -11,10 +11,12 @@ def self.max(array)
 
   	array.each_with_index do |item, index| 
   		if (array[index] > x)
-  			x = array[index]
-  		end
+        x = array[index]
+      end
   	end
-		x
+
+    x
+
   end
 
 
@@ -25,12 +27,18 @@ def self.max(array)
 
 
   def self.middle_element(array)
-  
-  	if array.length % 2 == 1
-  		return array[array.length]
-  	# else
-  	# 	return [array[z], array[(z+1)]]
-  	end
+
+    mid_index_neg_length = array.length / 2
+    mid_neg_value = array[mid_index_neg_length]
+
+    if array.empty?
+      nil
+    elsif array.length.odd?
+      mid_neg_value
+    else
+      (mid_neg_value + array[(mid_index_neg_length-1)]) / 2.0
+    end
+
   end
 
 
@@ -43,6 +51,15 @@ def self.middle_element(array)
 
 
   def self.sum_arrays(array1, array2)
+    
+    array3 = []
+
+    array1.each_with_index do |x,y|
+      array3 << (x + array2[y])
+    end
+
+    array3
 
   end
+
 end