Arrays

array_problems/arrays.rb

@@ -3,11 +3,27 @@
 
 module ArrayUtil
   def self.max(array)
+    #I found this solution in the Pry Debugger notes. I think it would take some time to execute because I assume it goes through every item in the array, since it's an inject. 
+    array.inject {|y, x| x > y ? x : y }
   end
 
   def self.middle_element(array)
+    #I don't think these would require too much time because the if/else is based on the array length, which is pre-defined in the array.
+    if array.length == 0
+      nil
+    elsif array.length % 2 == 0
+      mid = array.length/2
+      (array[mid] + array[mid - 1])/2.to_f
+    else
+    mid = array.length/2
+    array[mid] 
+    end
   end
 
   def self.sum_arrays(array1, array2)
+    #This one might take some time because the each will have to run through every element of two arrays. 
+    sum = []
+    array1.each_index {|i| sum.push(array1[i] + array2[i]) }
+    sum
   end
 end

set1/set1.rb

@@ -1,10 +1,61 @@
 module Set1
+  # I think this method is O(n)
   def self.swap_small(array)
+    if array.length == 1
+      return array
+    else
+      min = array.first
+      array.each do |n|
+        if n < min 
+          min = n
+        end
+    end
+    array[array.index(min)] = array.first
+    array[0] = min
+    array
   end
-
+end
+# I think this method is O(n^2)
   def self.find_sum_2(array, sum = 0)
+    if array.include?(sum)
+      return true
+    elsif array.empty?
+      return false
+    else
+      array.each_index do |x|
+        array.each_index do |y|
+          if array[x] + array[y] == 0
+            return true
+          end
+        end
+      end
+    end
+    false
   end
 
+#I think this method is O(n^3)
   def self.find_sum_3(array)
+   if array.include?(0)
+      return true
+    elsif array.empty?
+      return false
+    else
+      array.each_index do |x|
+        array.each_index do |y|
+          array.each_index do |z|
+          if array[x] + array[y] + array[z] == 0
+            return true
+          end
+          end
+        end
+      end
+    end
+    false
   end
+
 end
+
+
+
+
+