Solution to problem1 with rspec tests.

Author: deepakhb2

lib/Problems/daily-coding-problems/find_min_max_ary.rb

@@ -0,0 +1,35 @@
+# Given an array of numbers of length N, find both the minimum and maximum using less than 2 * (N - 2) comparisons.
+
+class Problems
+  def self.find_min_max_in_ary(values)
+    min, max = 0, 0
+    comparisons = 0
+    comparisons += 1
+    if(values.size == 1)
+      min = values[0]
+      max = values[0]
+      return min, max
+    end
+    comparisons += 1
+    if(values[0] <= values[1])
+      min = values[0]
+      max = values[1]
+    else
+      min = values[1]
+      max = values[0]
+    end
+    values.shift
+    values.shift
+    values.each do |value|
+      comparisons += 1
+      if(value < min)
+        min = value
+      end
+      comparisons += 1
+      if(value > max)
+        max = value
+      end
+    end
+    [min, max, comparisons]
+  end
+end

lib/Problems/daily-coding-problems/problem1.rb

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+# Given a list of numbers and a number k, return whether any two numbers
+# from the list add up to k.
+#
+# For example, given [10, 15, 3, 7] and k of 17, return true since 10 +
+# 7 is 17.
+#
+# Asumptions:
+# The given array and k will always contain positive numbers.
+#
+class Problem1
+  def self.solution(values, k)
+    size = values.size
+    if(size <= 1 || k < 1)
+      return false
+    elsif(size == 2)
+      return (values[0] + values[1]) == k
+    end
+    (0...size).each do |i|
+      (1...size).each do |j|
+        if(values[i]+values[j] == k)
+          return true
+        end
+      end
+    end
+    return false
+  end
+end

spec/Problems/daily-coding-problems/find_min_max_ary_spec.rb

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+describe Problems do
+
+  # Given an array of numbers of length N, find both the minimum and
+  # maximum using less than 2 * (N - 2) comparisons.
+  describe '#find_min_max_in_ary' do
+    it 'return min and max value of array with "2 * (n-1)" comparison' do
+      values = [9, 2, 4, 6, 10, 1]
+      comparisons = 2 * (values.length - 2)
+      expect(Problems.find_min_max_in_ary(values)).to eq([1, 10, comparisons])
+    end
+  end
+end

spec/Problems/daily-coding-problems/problem1_spec.rb

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+# Given a list of numbers and a number k, return whether any two numbers
+# from the list add up to k.
+#
+# For example, given [10, 15, 3, 7] and k of 17, return true since 10 +
+# 7 is 17.
+
+describe Problem1 do
+  describe '#solution' do
+    context 'Valid inputs' do
+      it 'Return false when array size greater than 2' do
+        values = [10, 15, 3, 7]
+        k = 15
+        expect(described_class.solution(values, k)).to eq(false)
+      end
+
+      it 'Return true when array size greater than 2' do
+        values = [10, 15, 3, 7]
+        k = 17
+        expect(described_class.solution(values, k)).to eq(true)
+      end
+
+      it 'Return false when array size is 2' do
+        values = [10, 15]
+        k = 15
+        expect(described_class.solution(values, k)).to eq(false)
+      end
+
+      it 'Rreturn true when array size is 2' do
+        values = [10, 15]
+        k = 25
+        expect(described_class.solution(values, k)).to eq(true)
+      end
+    end
+
+    context 'Invalid Inputs' do
+      it 'Return false when k value is negative' do
+        values = [10, 15]
+        k = -35
+        expect(described_class.solution(values, k)).to eq(false)
+      end
+
+      it 'Return false when array size is 1' do
+        values = [10]
+        k = 35
+        expect(described_class.solution(values, k)).to eq(false)
+      end
+    end
+  end
+end