Arrays and Set 1 Pull Request

algorithms.rb

@@ -0,0 +1,26 @@
+def max(array)
+	return "No array provided." if array.length == 0
+	highest = array[0]
+	array[1..-1].each {|x| highest = x if highest < x }
+	return highest
+end
+
+
+def middle_element(array)
+	return "No array provided." if array.length == 0
+	length = array.sort!.length
+	p array
+	p length
+	if length % 2 == 0
+		return (array[length/2-1] + array[length/2])/2.0
+	else
+		return array[length/2]
+	end
+end
+
+def sum_arrays(array1, array2)
+	arr = []
+	l = array1.length
+	0.upto(l-1) {|x| arr[x] = array1[x]+array2[x]}
+	return arr
+end

array_problems/arrays.rb

@@ -3,11 +3,26 @@
 
 module ArrayUtil
   def self.max(array)
+    return nil if array.empty?
+    highest = array[0]
+    array[1..-1].each {|x| highest = x if highest < x }
+    return highest
   end
 
+
   def self.middle_element(array)
+    return nil if array.empty?
+    length = array.sort!.length
+    if length % 2 == 0
+      return (array[length/2-1] + array[length/2])/2.0
+    else
+      return array[length/2]
+    end
   end
 
   def self.sum_arrays(array1, array2)
+    arr = []
+    0.upto(array1.length-1) {|x| arr[x] = array1[x]+array2[x]}
+    return arr
   end
 end

set1/set1.rb

@@ -1,10 +1,38 @@
 module Set1
   def self.swap_small(array)
+    small = array[0]
+    ar2 = [0]
+    array[1..-1].each do |x|
+      if x < small
+        ar2.push(small)
+        small = x
+      else
+        ar2.push(x)
+      end
+    end
+    ar2[0]=(small)
+    ar2
   end
 
   def self.find_sum_2(array, sum = 0)
+    return false if array.empty?
+    array.each do |ar1|
+      array.each do |ar2|
+        return true if (ar1 + ar2) == 0
+      end
+    end
+    return false
   end
 
   def self.find_sum_3(array)
+    return false if array.empty?
+    array.each do |ar1|
+      array.each do |ar2|
+        array.each do |ar3|
+          return true if (ar1+ar2+ar3)==0
+        end
+      end
+    end
+    return false
   end
 end

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