Arrays

array_problems/arrays.rb

@@ -3,11 +3,32 @@
 
 module ArrayUtil
   def self.max(array)
+    # if array.empty?      dont' need
+    #   return nil
+    # else
+      max = array.first
+      array.each do |x|
+        if x >= max 
+        max = x
+        end
+      end
+    end
+    return max
   end
 
   def self.middle_element(array)
+     return nil if array.empty?
+      mid = array.length / 2
+      if array.length.even?
+        return (array[mid] + array[mid - 1]) / 2.0
+      else
+        return array[mid]
+      end 
+    end
   end
 
   def self.sum_arrays(array1, array2)
+    solution = [array1.each_index { |x| array1[x] + array2[x]}]
+    solution
   end
 end

array_problems/spec/arrays_spec.rb

@@ -35,6 +35,7 @@
       expect(ArrayUtil.max([-1, -5, -10, -2])).to eq(-1)
     end
   end
+end
 
   describe ".middle_element" do
     it "should return nil for an empty array" do

set1/set1.rb

@@ -1,10 +1,71 @@
 module Set1
   def self.swap_small(array)
+    if array.length == 1 
+      return array
+    else
+      min_num = array.first
+      array.each do |x|
+        if x <= min_num
+          min_num = x
+        end
+      end
+      array[array.index(min_num)] = array.first
+      array[0] = min_num
+      array
+    end
   end
 
+  # def self.find_sum_2(array, sum = 0)
+  #   if array.length == 0 
+  #     return false
+  #   elsif array.include?(0)
+  #     return true
+  #   elsif array.each { |x| array.include?(x) && array.include?(-x) }
+  #     return true
+  #   else # Can not get this one to work!!!
+  #     array.each { |x| sum += x }
+  #     if sum.equ?(0)
+  #       return false
+  #     else 
+  #       return true
+  #     end
+  #   end
+  # end
+
   def self.find_sum_2(array, sum = 0)
+    array.each do |elem1|
+      array.each do |elem2|
+        if elem1 + elem2 == sum
+          return true
+        end
+      end
+    end
+    false
+  end
+
+  def self.fin_sum_2(array, sum = 0)
+    hash = {}
+    array.each do |elem1|
+      hash[elem1] = true
+    end
+    array.each do |elem1|
+      if hash[sum - elem1]
+        return true
+      end
+    end
+    false
   end
 
   def self.find_sum_3(array)
+   array.each do |elem1|
+    array.each do |elem2|
+      array.each do |elem3|
+        if elem1 + elem2 + elem3 == 0
+        return true
+        end
+      end
+    end
+  end
+  false
   end
 end

set1/spec/set1_spec.rb

@@ -24,19 +24,19 @@
   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
@@ -47,11 +47,11 @@
   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