Arrays

array_problems/arrays.rb

@@ -3,9 +3,23 @@
 
 module ArrayUtil
   def self.max(array)
+    biggest= array[0]
+    array.each_with_index do |x, i| 
+      if array[(i+1)] > biggest
+        biggest = x
+        binding.pry
+      end
+    end
+    biggest
   end
 
   def self.middle_element(array)
+    if array.length % 2 == 0
+      #array is even length
+      array.each_with_index do |x,i|
+
+      end
+
   end
 
   def self.sum_arrays(array1, array2)

set1/set1.rb

@@ -1,10 +1,77 @@
 module Set1
-  def self.swap_small(array)
+  def self.swap_small(array) #darrell & Jimmy
+    #.each_index
+    if array.count == 1
+      return array
+    end
+    smallest_number = array[0]
+    smallest_index = 0
+    array.each_with_index do |value, index|
+      if value < smallest_number
+        smallest_number = value
+        smallest_index = index
+      end
+    end
+    if smallest_number == array[0]
+      return array
+    end
+    array.delete_at(smallest_index)
+    temp = array[0]
+    array.delete(array[0])
+    array.unshift(smallest_number)
+    array.insert(smallest_index, temp)
+    array
   end
 
   def self.find_sum_2(array, sum = 0)
+    #Given an array of numbers, find out if there are two numbers in 
+    #the array that add up to 0 (just return true or false). You can use 
+    #the same number multiple times.
+    if array.count == 0
+      false
+    elsif array.include?(0)
+      true
+    elsif array[0] == 0
+      true
+    else  
+      flag = false
+      array.each do |x|
+        array.each do |y|
+          if x + y == sum
+            flag = true #inefficient because it will continue to run
+            #even after the conditions has been satisified until
+            #it hits the end
+          end
+        end
+      end
+      flag
+    end
   end
 
   def self.find_sum_3(array)
+    if array.count == 0
+      false
+    elsif array.include?(0)
+      true
+    elsif array[0] == 0
+      true
+    else  
+      flag = false
+      array.each do |x|
+        array.each do |y|
+          array.each do |z|
+            sum = x + y + z
+            if sum == 0
+              flag = true
+            end
+          end
+        end
+      end
+      flag
+    end
   end
 end
+#WHILE WORKING THROUGH THESE TYPES OF PROBLEMS. Think about how 
+#we are thinking about them. Examine our own thought process
+#because we will be evaluated on that during interviews. 
+

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