From e21120857dd0a16c7512919fc047814690b9eb22 Mon Sep 17 00:00:00 2001
From: Vitor Oliveira <vbrazo@gmail.com>
Date: Sat, 6 Feb 2021 23:05:54 -0800
Subject: [PATCH] Clean up

---
 Searches/jump_search.rb                       | 50 ++++++-------
 ciphers/merkle_hellman_cryptosystem.rb        | 71 ++++++++++---------
 .../get_products_of_all_other_elements.rb     | 50 +++++++------
 .../binary_trees/inorder_traversal.rb         |  6 +-
 data_structures/binary_trees/invert.rb        |  9 ++-
 .../binary_trees/postorder_traversal.rb       |  6 +-
 .../binary_trees/preorder_traversal.rb        |  6 +-
 data_structures/linked_lists/double_list.rb   |  4 +-
 data_structures/linked_lists/single_list.rb   |  4 +-
 discrete_mathematics/euclidean_gcd.rb         | 10 +--
 .../exteded_euclidean_algorithm.rb            | 35 +++++----
 discrete_mathematics/lcm.rb                   | 12 ++--
 maths/binary_to_decimal.rb                    | 38 +++++-----
 maths/number_of_digits.rb                     | 30 ++++----
 maths/sum_of_digits.rb                        | 11 +--
 other/fisher_yates.rb                         |  8 +--
 project_euler/problem_2/sol1.rb               |  2 +-
 project_euler/problem_3/sol1.rb               |  2 +-
 project_euler/problem_3/sol2.rb               |  2 +-
 project_euler/problem_4/sol1.rb               |  2 +-
 project_euler/problem_5/sol1.rb               |  3 +-
 searches/binary_search.rb                     | 20 +++---
 searches/depth_first_search.rb                | 14 ++--
 searches/linear_search.rb                     | 14 ++--
 searches/ternary_search.rb                    | 68 +++++++++---------
 sorting/bogo_sort.rb                          | 13 ++--
 sorting/bubble_sort.rb                        | 44 ++++++------
 sorting/bucket_sort.rb                        | 59 ++++++++-------
 sorting/heap_sort.rb                          | 13 ++--
 sorting/insertion_sort.rb                     | 34 ++++-----
 sorting/merge_sort.rb                         | 17 ++---
 sorting/quicksort.rb                          |  2 +-
 sorting/selection_sort.rb                     |  2 +-
 sorting/shell_sort.rb                         | 31 ++++----
 34 files changed, 344 insertions(+), 348 deletions(-)

diff --git a/Searches/jump_search.rb b/Searches/jump_search.rb
index 899b9af..fc43663 100644
--- a/Searches/jump_search.rb
+++ b/Searches/jump_search.rb
@@ -3,46 +3,40 @@
 # Time Complexity: O(√n)
 
 def jump_search(arr, x)
-  n = arr.length;
+  n = arr.length
 
-  # Finding block size to be jumped 
-  step = Math.sqrt(n);
-  prev = 0;
+  # Finding block size to be jumped
+  step = Math.sqrt(n)
+  prev = 0
 
-  # Finding the block where element is 
-  # present (if it is present) 
-  while (arr[[step, n].min - 1] < x) do
-    prev = step;
-    step += Math.sqrt(n);
-    if (prev >= n)
-      return -1;
-    end
+  # Finding the block where element is
+  # present (if it is present)
+  while arr[[step, n].min - 1] < x
+    prev = step
+    step += Math.sqrt(n)
+    return -1 if prev >= n
   end
 
-  # Doing a linear search for x in block 
-  # beginning with prev. 
-  while (arr[prev] < x) do
-    prev = prev + 1;
-    # If we reached next block or end of 
-    # array, element is not present. 
-    if (prev == [step, n].min)
-      return -1;
-    end
+  # Doing a linear search for x in block
+  # beginning with prev.
+  while arr[prev] < x
+    prev += 1
+    # If we reached next block or end of
+    # array, element is not present.
+    return -1 if prev == [step, n].min
   end
 
   # If element is found
-  if (arr[prev] == x)
-    return prev;
-  end
+  return prev if arr[prev] == x
 
-  return -1;
+  -1
 end
 
-puts "Enter a sorted space-separated list:"
+puts 'Enter a sorted space-separated list:'
 arr = gets.chomp.split(' ').map(&:to_i)
-puts "Enter the value to be searched:"
+puts 'Enter the value to be searched:'
 value = gets.chomp.to_i
 
 index = jump_search(arr, value)
 
-puts index == -1 ? "Element not found" : "Number #{value} is at #{index}"
+puts index == -1 ? 'Element not found' : "Number #{value} is at #{index}"
diff --git a/ciphers/merkle_hellman_cryptosystem.rb b/ciphers/merkle_hellman_cryptosystem.rb
index 42bfbfe..5676c69 100755
--- a/ciphers/merkle_hellman_cryptosystem.rb
+++ b/ciphers/merkle_hellman_cryptosystem.rb
@@ -1,64 +1,65 @@
-require'openssl';
+require 'openssl'
 
 class MerkleHellman
   SMALLEST_KNAPSACK_ITEM = 2**32
   STEP = 2**32
 
-  def initialize size
-    @size = size;
-    sum = SMALLEST_KNAPSACK_ITEM;
-    @easy_knapsack = size.times.map do |k|
-      x = sum + rand(STEP);
-      sum += x;
-      x;
+  def initialize(size)
+    @size = size
+    sum = SMALLEST_KNAPSACK_ITEM
+    @easy_knapsack = size.times.map do |_k|
+      x = sum + rand(STEP)
+      sum += x
+      x
     end
-    @n = sum + rand(STEP);
+    @n = sum + rand(STEP)
 
     loop do
-      @a = rand(0..@n);
-      break if @a.gcd(@n) == 1;
+      @a = rand(0..@n)
+      break if @a.gcd(@n) == 1
     end
 
     @hard_knapsack = @easy_knapsack.map do |x|
-      (@a * x) % @n;
+      (@a * x) % @n
     end
   end
 
-  def encrypt msg
-    raise ArgumentError, "max length is #{@size/8} characters" if msg.length * 8 > @size;
-    c = 0;
-    msg.each_codepoint.reverse_each.with_index do |ch,i|
-      7.downto(0) do|j|
-        wj = ch.>>(j).& 1;
-        c += wj * @hard_knapsack[i*8+7-j]
+  def encrypt(msg)
+    raise ArgumentError, "max length is #{@size / 8} characters" if msg.length * 8 > @size
+
+    c = 0
+    msg.each_codepoint.reverse_each.with_index do |ch, i|
+      7.downto(0) do |j|
+        wj = ch.>>(j).& 1
+        c += wj * @hard_knapsack[i * 8 + 7 - j]
       end
     end
-    c;
+    c
   end
 
-  def decrypt c
-    p = @a.to_bn.mod_inverse(@n).mod_mul(c,@n).to_i;
-    byte = 0;
-    msg = [ ];
-    @easy_knapsack.reverse_each.with_index do |x,i|
-      bit = 0;
+  def decrypt(c)
+    p = @a.to_bn.mod_inverse(@n).mod_mul(c, @n).to_i
+    byte = 0
+    msg = []
+    @easy_knapsack.reverse_each.with_index do |x, i|
+      bit = 0
       if p >= x
-        p -= x;
-        bit = 1;
+        p -= x
+        bit = 1
       end
-      byte |= (bit << (i%8));
+      byte |= (bit << (i % 8))
       if i % 8 == 7
-        msg << byte.chr;
-        byte = 0;
+        msg << byte.chr
+        byte = 0
       end
     end
-    msg.join;
+    msg.join
   end
-  attr_accessor :hard_knapsack;
+  attr_accessor :hard_knapsack
 end
 
-str = "Hello there, this is my plaintext";
-mh = MerkleHellman.new(str.length*8)
+str = 'Hello there, this is my plaintext'
+mh = MerkleHellman.new(str.length * 8)
 puts "[*] Encrypting \"#{str}\""
 
 c = mh.encrypt(str)
diff --git a/data_structures/arrays/get_products_of_all_other_elements.rb b/data_structures/arrays/get_products_of_all_other_elements.rb
index 0e7d97d..467ac65 100644
--- a/data_structures/arrays/get_products_of_all_other_elements.rb
+++ b/data_structures/arrays/get_products_of_all_other_elements.rb
@@ -11,11 +11,9 @@
 def calculate_products_of_all_other_elements(nums)
   product_of_other_elements = Array.new(nums.length, 1)
 
-  nums.each_with_index do |num1, i|
+  nums.each_with_index do |_num1, i|
     nums.each_with_index do |num2, j|
-      if (i != j)
-        product_of_other_elements[i] = product_of_other_elements[i] * num2
-      end
+      product_of_other_elements[i] = product_of_other_elements[i] * num2 if i != j
     end
   end
 
@@ -34,14 +32,14 @@ def build_prefix_products(nums)
   prefix_products = []
 
   nums.each do |num|
-    if prefix_products.count > 0
-      prefix_products << (prefix_products.last * num)
-    else
-      prefix_products << num
-    end
+    prefix_products << if prefix_products.count > 0
+                         (prefix_products.last * num)
+                       else
+                         num
+                       end
   end
 
-  return prefix_products
+  prefix_products
 end
 
 # Generates suffix products
@@ -49,31 +47,31 @@ def build_suffix_products(nums)
   suffix_products = []
 
   nums.reverse.each do |num|
-    if suffix_products.count > 0
-      suffix_products << (suffix_products.last * num)
-    else
-      suffix_products << num
-    end
+    suffix_products << if suffix_products.count > 0
+                         (suffix_products.last * num)
+                       else
+                         num
+                       end
   end
 
-  return suffix_products
+  suffix_products
 end
 
 # Builds output
 def output(prefix_products, suffix_products, nums)
   result = []
 
-  nums.reverse.each_with_index do |num, index|
-    if index == 0
-      result << suffix_products[index + 1]
-    elsif index == nums.length - 1
-      result << prefix_products[index - 1]
-    else
-      result << (prefix_products[index - 1] * suffix_products[index + 1])
-    end
+  nums.reverse.each_with_index do |_num, index|
+    result << if index == 0
+                suffix_products[index + 1]
+              elsif index == nums.length - 1
+                prefix_products[index - 1]
+              else
+                (prefix_products[index - 1] * suffix_products[index + 1])
+              end
   end
 
-  return result
+  result
 end
 
 # Generate result from the product of prefixes and suffixes
@@ -82,7 +80,7 @@ def products(nums)
   suffix_products = build_suffix_products(nums)
   suffix_products = suffix_products.reverse
 
-  return output(prefix_products, suffix_products, nums)
+  output(prefix_products, suffix_products, nums)
 end
 
 puts(products([1, 2, 3]))
diff --git a/data_structures/binary_trees/inorder_traversal.rb b/data_structures/binary_trees/inorder_traversal.rb
index 779f76a..3e5dbca 100644
--- a/data_structures/binary_trees/inorder_traversal.rb
+++ b/data_structures/binary_trees/inorder_traversal.rb
@@ -12,12 +12,12 @@
 def inorder_traversal(root)
   ans = []
   def traverse(node, ans)
-    if node != nil
+    unless node.nil?
       traverse(node.left, ans)
       ans.push(node.val)
       traverse(node.right, ans)
     end
   end
   traverse(root, ans)
-  return ans
-end
\ No newline at end of file
+  ans
+end
diff --git a/data_structures/binary_trees/invert.rb b/data_structures/binary_trees/invert.rb
index 7ccc10d..984389f 100644
--- a/data_structures/binary_trees/invert.rb
+++ b/data_structures/binary_trees/invert.rb
@@ -10,11 +10,10 @@
 # @param {TreeNode} root
 # @return {TreeNode}
 def invert_tree(root)
-  if root == nil
-    return nil
-  end
+  return nil if root.nil?
+
   temp = root.left
   root.left = invert_tree(root.right)
   root.right = invert_tree(temp)
-  return root
-end
\ No newline at end of file
+  root
+end
diff --git a/data_structures/binary_trees/postorder_traversal.rb b/data_structures/binary_trees/postorder_traversal.rb
index a8440e6..62f6447 100644
--- a/data_structures/binary_trees/postorder_traversal.rb
+++ b/data_structures/binary_trees/postorder_traversal.rb
@@ -12,12 +12,12 @@
 def postorder_traversal(root)
   ans = []
   def traverse(node, ans)
-    if node != nil
+    unless node.nil?
       traverse(node.left, ans)
       traverse(node.right, ans)
       ans.push(node.val)
     end
   end
   traverse(root, ans)
-  return ans
-end
\ No newline at end of file
+  ans
+end
diff --git a/data_structures/binary_trees/preorder_traversal.rb b/data_structures/binary_trees/preorder_traversal.rb
index 74db171..94b0ab8 100644
--- a/data_structures/binary_trees/preorder_traversal.rb
+++ b/data_structures/binary_trees/preorder_traversal.rb
@@ -12,12 +12,12 @@
 def preorder_traversal(root)
   ans = []
   def traverse(node, ans)
-    if node != nil
+    unless node.nil?
       ans.push(node.val)
       traverse(node.left, ans)
       traverse(node.right, ans)
     end
   end
   traverse(root, ans)
-  return ans
-end
\ No newline at end of file
+  ans
+end
diff --git a/data_structures/linked_lists/double_list.rb b/data_structures/linked_lists/double_list.rb
index 9d5508c..9ec583a 100644
--- a/data_structures/linked_lists/double_list.rb
+++ b/data_structures/linked_lists/double_list.rb
@@ -1,6 +1,7 @@
 # Define a node in the list
 class Node
   attr_accessor :value, :next, :prev
+
   def initialize(value)
     @value = value
     @next = nil
@@ -12,6 +13,7 @@ end
 class DoubleList
   include Enumerable
   attr_accessor :head, :tail
+
   def initialize
     @head = nil
     @tail = nil
@@ -67,7 +69,7 @@ class DoubleList
 
   def print_list
     # the to_a method is from Enumerable, will call each to get the values, and return an array
-    puts '[' + self.to_a.join(', ') + ']'
+    puts '[' + to_a.join(', ') + ']'
   end
 
   def empty?
diff --git a/data_structures/linked_lists/single_list.rb b/data_structures/linked_lists/single_list.rb
index aa0f4f8..955bf44 100644
--- a/data_structures/linked_lists/single_list.rb
+++ b/data_structures/linked_lists/single_list.rb
@@ -1,6 +1,7 @@
 # Define a node in the list
 class Node
   attr_accessor :value, :next
+
   def initialize(value)
     @value = value
     @next = nil
@@ -12,6 +13,7 @@ end
 class SingleList
   include Enumerable
   attr_accessor :head
+
   def initialize
     @head = nil
   end
@@ -48,7 +50,7 @@ class SingleList
   end
 
   def print_list
-    puts '[' + self.to_a.join(', ') + ']'
+    puts '[' + to_a.join(', ') + ']'
   end
 
   def delete_head
diff --git a/discrete_mathematics/euclidean_gcd.rb b/discrete_mathematics/euclidean_gcd.rb
index 4d3c8c4..b3a27c6 100644
--- a/discrete_mathematics/euclidean_gcd.rb
+++ b/discrete_mathematics/euclidean_gcd.rb
@@ -1,4 +1,4 @@
-#https://en.wikipedia.org/wiki/Euclidean_algorithm
+# https://en.wikipedia.org/wiki/Euclidean_algorithm
 
 def euclidean_gcd(a, b)
   while b != 0
@@ -6,9 +6,9 @@ def euclidean_gcd(a, b)
     b = a % b
     a = t
   end
-  return a
+  a
 end
 
-puts "GCD(3, 5) = " + euclidean_gcd(3, 5).to_s
-puts "GCD(3, 6) = " + euclidean_gcd(3, 6).to_s
-puts "GCD(6, 3) = " + euclidean_gcd(6, 3).to_s
+puts 'GCD(3, 5) = ' + euclidean_gcd(3, 5).to_s
+puts 'GCD(3, 6) = ' + euclidean_gcd(3, 6).to_s
+puts 'GCD(6, 3) = ' + euclidean_gcd(6, 3).to_s
diff --git a/discrete_mathematics/exteded_euclidean_algorithm.rb b/discrete_mathematics/exteded_euclidean_algorithm.rb
index afd955e..07afd86 100644
--- a/discrete_mathematics/exteded_euclidean_algorithm.rb
+++ b/discrete_mathematics/exteded_euclidean_algorithm.rb
@@ -1,31 +1,30 @@
 # https://en.wikipedia.org/wiki/Extended_Euclidean_algorithm
 
 def extended_euclidean_gcd(a, b)
-
-  x0, x1 = a, b
-  s, t = 1, 0
+  x0 = a
+  x1 = b
+  s = 1
+  t = 0
   until x1.zero?
     q, x2 = x0.divmod(x1)
-    x0, x1 = x1, x2
+    x0 = x1
+    x1 = x2
     s, t = t, s - q * t
   end
-  gcd = x0
-  return gcd
+  x0
 end
 
-puts "GCD(3, 5) = " + extended_euclidean_gcd(3, 5).to_s
+puts 'GCD(3, 5) = ' + extended_euclidean_gcd(3, 5).to_s
 # GCD(3, 5) = 1
-puts "GCD(3, 6) = " + extended_euclidean_gcd(3, 6).to_s
+puts 'GCD(3, 6) = ' + extended_euclidean_gcd(3, 6).to_s
 # GCD(3, 6) = 3
-puts "GCD(6, 3) = " + extended_euclidean_gcd(6, 3).to_s
+puts 'GCD(6, 3) = ' + extended_euclidean_gcd(6, 3).to_s
 # GCD(6, 3) = 3
 
-=begin
-
-Dynamic driver code:
-
-a = gets.to_i
-b = gets.to_i
-puts "GCD (#{a}, #{b} ) = #{extended_euclidean_gcd(a, b)}"
-
-=end
+#
+# Dynamic driver code:
+#
+# a = gets.to_i
+# b = gets.to_i
+# puts "GCD (#{a}, #{b} ) = #{extended_euclidean_gcd(a, b)}"
+#
diff --git a/discrete_mathematics/lcm.rb b/discrete_mathematics/lcm.rb
index 69af88c..3409ddb 100644
--- a/discrete_mathematics/lcm.rb
+++ b/discrete_mathematics/lcm.rb
@@ -1,23 +1,23 @@
 # LCM (Least Common Multiple) of two numbers is the smallest number which can be divided by both numbers.
 
-p "Least Common Multiple"
+p 'Least Common Multiple'
 
-p "Enter first number"
+p 'Enter first number'
 value_one = gets.chomp.to_i
 
-p "Enter second number"
+p 'Enter second number'
 value_two = gets.chomp.to_i
 
 def gcd(first, second)
   if second != 0
-    gcd(second, first%second)
+    gcd(second, first % second)
   else
     first
   end
 end
 
 def lcm(first, second)
-  (first * second)/gcd(first, second)
+  (first * second) / gcd(first, second)
 end
 
-p "Least Common Multiple is: #{lcm(value_one, value_two)}"
\ No newline at end of file
+p "Least Common Multiple is: #{lcm(value_one, value_two)}"
diff --git a/maths/binary_to_decimal.rb b/maths/binary_to_decimal.rb
index af4c7b8..972e088 100644
--- a/maths/binary_to_decimal.rb
+++ b/maths/binary_to_decimal.rb
@@ -1,26 +1,24 @@
-=begin
-
-For any binary number of n digits i.e dn-1 ... d3 d2 d1 d0
-The equivalent decimal number is equal to the sum of binary digits (dn) times their power of 2 (2n):
-decimal = d0×2^0 + d1×2^1 + d2×2^2 + ...
-
-=end
+#
+# For any binary number of n digits i.e dn-1 ... d3 d2 d1 d0
+# The equivalent decimal number is equal to the sum of binary digits (dn) times their power of 2 (2n):
+# decimal = d0×2^0 + d1×2^1 + d2×2^2 + ...
+#
 
 def binary_to_decimal(n)
-    decimal = 0
-    base = 1
-    until n.zero?
-        x = n % 10
-        n /= 10
-        decimal += x * base
-        base *= 2
-    end
-    return decimal
+  decimal = 0
+  base = 1
+  until n.zero?
+    x = n % 10
+    n /= 10
+    decimal += x * base
+    base *= 2
+  end
+  decimal
 end
-    
-puts "Decimal value of 110011 is " + binary_to_decimal(110011).to_s
+
+puts 'Decimal value of 110011 is ' + binary_to_decimal(110_011).to_s
 # Decimal value of 110011 is 51
-puts "Decimal value of 11110 is " + binary_to_decimal(11110).to_s
+puts 'Decimal value of 11110 is ' + binary_to_decimal(11_110).to_s
 # Decimal value of 11110 is 30
-puts "Decimal value of 101 is " + binary_to_decimal(101).to_s
+puts 'Decimal value of 101 is ' + binary_to_decimal(101).to_s
 # Decimal value of 101 is 5
diff --git a/maths/number_of_digits.rb b/maths/number_of_digits.rb
index f14b567..66552e5 100644
--- a/maths/number_of_digits.rb
+++ b/maths/number_of_digits.rb
@@ -1,24 +1,22 @@
 # Given a number, find number of digits in it.
 
 def count_digits(n)
-    count = 0
-    temp = n
-    
-    if (n == 0)
-        return 1
-    end
-    
-    until temp.zero?
-        count += 1
-        temp /= 10
-    end
-    
-    return count
+  count = 0
+  temp = n
+
+  return 1 if n == 0
+
+  until temp.zero?
+    count += 1
+    temp /= 10
+  end
+
+  count
 end
 
-puts "Number of digits in 8732 is " + count_digits(8732).to_s
+puts 'Number of digits in 8732 is ' + count_digits(8732).to_s
 # Number of digits in 8732 is 4
-puts "Number of digits in 112233 is " + count_digits(112233).to_s
+puts 'Number of digits in 112233 is ' + count_digits(112_233).to_s
 # Number of digits in 112233 is 6
-puts "Number of digits in 0 is " + count_digits(0).to_s
+puts 'Number of digits in 0 is ' + count_digits(0).to_s
 # Number of digits in 0 is 1
diff --git a/maths/sum_of_digits.rb b/maths/sum_of_digits.rb
index 0ea0794..a19b197 100644
--- a/maths/sum_of_digits.rb
+++ b/maths/sum_of_digits.rb
@@ -1,18 +1,19 @@
 # Given a number, find sum of its digits.
 
 def digits_sum(n)
-  a, sum = 0, 0
+  a = 0
+  sum = 0
   until n.zero?
     a = n % 10
     sum += a
     n /= 10
   end
-  return sum
+  sum
 end
 
-puts "Sum of digits of 3456 is " + digits_sum(3456).to_s
+puts 'Sum of digits of 3456 is ' + digits_sum(3456).to_s
 # Sum of digits of 3456 is 18
-puts "Sum of digits of 1234 is " + digits_sum(1234).to_s
+puts 'Sum of digits of 1234 is ' + digits_sum(1234).to_s
 # Sum of digits of 1234 is 10
-puts "Sum of digits of 9251321 is " + digits_sum(9251321).to_s
+puts 'Sum of digits of 9251321 is ' + digits_sum(9_251_321).to_s
 # Sum of digits of 9251321 is 23
diff --git a/other/fisher_yates.rb b/other/fisher_yates.rb
index 8496c4f..46cf2af 100644
--- a/other/fisher_yates.rb
+++ b/other/fisher_yates.rb
@@ -1,12 +1,12 @@
 # Fisher and Yates Shuffle is one of the simplest and most popular shuffling algorithm
 def fisher_yates_shuffle(array)
   n = array.length
-  while n > 0 
-    i = rand(n-=1)
+  while n > 0
+    i = rand(n -= 1)
     array[i], array[n] = array[n], array[i]
   end
-  return array
+  array
 end
 
 arr = [1, 2, 40, 30, 20, 15, 323, 12, 3, 4]
-puts fisher_yates_shuffle(arr)
\ No newline at end of file
+puts fisher_yates_shuffle(arr)
diff --git a/project_euler/problem_2/sol1.rb b/project_euler/problem_2/sol1.rb
index e514770..17b6214 100644
--- a/project_euler/problem_2/sol1.rb
+++ b/project_euler/problem_2/sol1.rb
@@ -8,7 +8,7 @@ even_fib_sum = 0
 fib_first = 1
 fib_second = 2
 
-while fib_second < 4000000
+while fib_second < 4_000_000
   even_fib_sum += fib_second if fib_second.even?
   fib_second += fib_first
   fib_first = fib_second - fib_first
diff --git a/project_euler/problem_3/sol1.rb b/project_euler/problem_3/sol1.rb
index 1401f44..df92cf0 100644
--- a/project_euler/problem_3/sol1.rb
+++ b/project_euler/problem_3/sol1.rb
@@ -26,4 +26,4 @@ def largest_prime_factor(number)
   prime_factors.max
 end
 
-puts largest_prime_factor(600851475143)
+puts largest_prime_factor(600_851_475_143)
diff --git a/project_euler/problem_3/sol2.rb b/project_euler/problem_3/sol2.rb
index b35e16d..0685de6 100644
--- a/project_euler/problem_3/sol2.rb
+++ b/project_euler/problem_3/sol2.rb
@@ -15,4 +15,4 @@ def solution(n)
   prime.to_i
 end
 
-puts solution(600851475143)
+puts solution(600_851_475_143)
diff --git a/project_euler/problem_4/sol1.rb b/project_euler/problem_4/sol1.rb
index fb1ac24..f3f52a2 100644
--- a/project_euler/problem_4/sol1.rb
+++ b/project_euler/problem_4/sol1.rb
@@ -8,4 +8,4 @@ answer = 0
     answer = i * j if (t.to_s == t.to_s.reverse) && (t > answer) && (t > answer)
   end
 end
-puts answer
\ No newline at end of file
+puts answer
diff --git a/project_euler/problem_5/sol1.rb b/project_euler/problem_5/sol1.rb
index 46997f0..e83cbfb 100644
--- a/project_euler/problem_5/sol1.rb
+++ b/project_euler/problem_5/sol1.rb
@@ -3,7 +3,6 @@
 # What is the smallest positive number that is evenly
 # divisible by all of the numbers from 1 to 20?
 
-
 # Euclid's algorithm for the greatest common divisor
 def gcd(a, b)
   b.zero? ? a : gcd(b, a % b)
@@ -20,4 +19,4 @@ result = 1
   result = lcm(result, i + 1)
 end
 
-p result
\ No newline at end of file
+p result
diff --git a/searches/binary_search.rb b/searches/binary_search.rb
index ca6fb1c..bbc8efa 100644
--- a/searches/binary_search.rb
+++ b/searches/binary_search.rb
@@ -1,15 +1,17 @@
-=begin
-Searches through a list for a value in O(log(n)) time.
-The list must be sorted.
-=end
+# Searches through a list for a value in O(log(n)) time.
+# The list must be sorted.
 def binary_search(array, key)
   front = 0
   back = array.length - 1
   while front <= back
     middle = (front + back) / 2
     return middle if array[middle] == key
-    key < array[middle] ?
-      back = middle - 1 : front = middle + 1
+
+    if key < array[middle]
+  back = middle - 1
+else
+  front = middle + 1
+end
   end
   nil
 end
@@ -18,6 +20,8 @@ puts "Enter a sorted space-separated list:"
 arr = gets.chomp.split(' ').map(&:to_i)
 puts "Enter the value to be searched:"
 value = gets.chomp.to_i
-puts binary_search(arr, value) != nil ?
-  "Found at index #{binary_search(arr, value)}" :
+puts if binary_search(arr, value) != nil
+  "Found at index #{binary_search(arr, value)}"
+else
   "Not found"
+end
diff --git a/searches/depth_first_search.rb b/searches/depth_first_search.rb
index e662235..6bb5a46 100644
--- a/searches/depth_first_search.rb
+++ b/searches/depth_first_search.rb
@@ -8,6 +8,7 @@ def dfs(start, target, adjacency_list)
   stack = [start]
   loop do
     break if stack.empty?
+
     current_node = stack.pop
     is_visited[current_node] = true
 
@@ -15,6 +16,7 @@ def dfs(start, target, adjacency_list)
 
     adjacency_list[current_node].each do |neighbor|
       next if is_visited[neighbor]
+
       stack << neighbor
       is_visited[neighbor] = true
       parent[neighbor] = current_node
@@ -38,12 +40,12 @@ end
 
 def main
   adjacency_list = [
-      [1, 2], #0
-      [0, 3], #1
-      [0, 3], #2
-      [1, 2, 4], #3
-      [3, 5], #4
-      [4] #5
+    [1, 2], # 0
+    [0, 3], # 1
+    [0, 3], # 2
+    [1, 2, 4], # 3
+    [3, 5], # 4
+    [4] # 5
   ]
   p dfs(0, 5, adjacency_list)
 end
diff --git a/searches/linear_search.rb b/searches/linear_search.rb
index 1f1964f..b8ef9df 100644
--- a/searches/linear_search.rb
+++ b/searches/linear_search.rb
@@ -1,18 +1,18 @@
-=begin
-Looks through array for a value in O(n) time.
-Array does not need to be sorted.
-=end
+# Looks through array for a value in O(n) time.
+# Array does not need to be sorted.
 def linear_search(array, key)
   array.each_with_index do |current, index|
     return index if current == key
   end
-  return nil
+  nil
 end
 
 puts "Enter a space-separated list:"
 arr = gets.chomp.split(' ').map(&:to_i)
 puts "Enter a value to be searched:"
 key = gets.chomp.to_i
-puts linear_search(arr, key) != nil ?
-  "Found at index #{linear_search(arr, key)}" :
+puts if linear_search(arr, key) != nil
+  "Found at index #{linear_search(arr, key)}"
+else
   "Not found"
+end
diff --git a/searches/ternary_search.rb b/searches/ternary_search.rb
index e8b622a..a8a6083 100644
--- a/searches/ternary_search.rb
+++ b/searches/ternary_search.rb
@@ -1,43 +1,43 @@
-=begin
-        Ternary Search
--------------------------------
-Ternary search is a searching technique that is used to search the position of a specific value in an array.
-Ternary search is a divide-and-conquer algorithm.
-It is mandatory for the array to be sorted (in which you will search for an element).
-The array is divided into three parts and then we determine in which part the element exists.
-In this search, after each iteration it neglects 1/3 part of the array and repeats the same operations on the remaining ⅔.
-Time Complexity: O(log3 n)
-Space Complexity: O(1)
-=end
+#         Ternary Search
+# -------------------------------
+# Ternary search is a searching technique that is used to search the position of a specific value in an array.
+# Ternary search is a divide-and-conquer algorithm.
+# It is mandatory for the array to be sorted (in which you will search for an element).
+# The array is divided into three parts and then we determine in which part the element exists.
+# In this search, after each iteration it neglects 1/3 part of the array and repeats the same operations on the remaining ⅔.
+# Time Complexity: O(log3 n)
+# Space Complexity: O(1)
 
 def ternary_search(l, r, key, arr)
-    #l is the starting index and r is the ending index of the array/sub-array.
-    if (r >= l)
-        #find mid1 and mid2
-        mid1 = l + (r - l) / 3
-        mid2 = r - (r - l) / 3
-        #check if key is equal to mid1
-        if arr[mid1] == key
-            mid1
-        #check if key is equal to mid2
-        elsif arr[mid2] == key
-            mid2
-        #Since key is not present at mid, check in which region it is present
-        #then repeat the Search operation in that region 
-        elsif key < arr[mid1] 
-            ternary_search(l, mid1 - 1, key, arr)
-        elsif (key > arr[mid2]) 
-            ternary_search(mid2 + 1, r, key, arr)
-        else 
-            ternary_search(mid1 + 1, mid2 - 1, key, arr) 
-        end
-    end
+    # l is the starting index and r is the ending index of the array/sub-array.
+  if r >= l
+      # find mid1 and mid2
+      mid1 = l + (r - l) / 3
+      mid2 = r - (r - l) / 3
+      # check if key is equal to mid1
+      if arr[mid1] == key
+          mid1
+      # check if key is equal to mid2
+      elsif arr[mid2] == key
+          mid2
+      # Since key is not present at mid, check in which region it is present
+      # then repeat the Search operation in that region
+      elsif key < arr[mid1]
+          ternary_search(l, mid1 - 1, key, arr)
+      elsif key > arr[mid2]
+          ternary_search(mid2 + 1, r, key, arr)
+      else
+          ternary_search(mid1 + 1, mid2 - 1, key, arr)
+      end
+  end
 end
 
 puts "Enter a space-separated list:"
 arr = gets.chomp.split(' ').map(&:to_i)
 puts "Enter a value to be searched:"
 key = gets.chomp.to_i
-puts ternary_search(0, arr.length - 1, key, arr) != nil ?
-  "Found at index #{ternary_search(0, arr.length - 1, key, arr)}" :
+puts if ternary_search(0, arr.length - 1, key, arr) != nil
+  "Found at index #{ternary_search(0, arr.length - 1, key, arr)}"
+else
   "Not found"
+end
diff --git a/sorting/bogo_sort.rb b/sorting/bogo_sort.rb
index c792026..8470458 100644
--- a/sorting/bogo_sort.rb
+++ b/sorting/bogo_sort.rb
@@ -1,20 +1,21 @@
 class Array
   def sorted?
     ### goes thru array and checks if all elements are in order
-    for i in 1...self.length
-      return false if self[i-1] > self[i]
+    (1...length).each do |i|
+      return false if self[i - 1] > self[i]
     end
-    return true
+    true
   end
+
   def bogosort
     ### randomly shuffles until sorted
-    self.shuffle! until self.sorted?
-    return self #return sorted array
+    shuffle! until sorted?
+    self # return sorted array
   end
 end
 
 if $0 == __FILE__
-  puts "Enter a list of numbers separated by space"
+  puts 'Enter a list of numbers separated by space'
   str = gets.chomp.split('')
   puts str.bogosort.join('')
 end
diff --git a/sorting/bubble_sort.rb b/sorting/bubble_sort.rb
index 0201431..6196b17 100644
--- a/sorting/bubble_sort.rb
+++ b/sorting/bubble_sort.rb
@@ -1,22 +1,22 @@
-def bubble_sort(array)
-  n = array.length
-  loop do
-    swapped = false
-
-    (n-1).times do |i|
-      if array[i] > array[i+1]
-        array[i], array[i+1] = array[i+1], array[i]
-        swapped = true
-      end
-    end
-
-    break if not swapped
-  end
-
-  array
-end
-puts "Enter a list of numbers separated by space"
-
-list = gets
-bubble_sort(list)
-print list
\ No newline at end of file
+def bubble_sort(array)
+  n = array.length
+  loop do
+    swapped = false
+
+    (n - 1).times do |i|
+      if array[i] > array[i + 1]
+        array[i], array[i + 1] = array[i + 1], array[i]
+        swapped = true
+      end
+    end
+
+    break unless swapped
+  end
+
+  array
+end
+puts 'Enter a list of numbers separated by space'
+
+list = gets
+bubble_sort(list)
+print list
diff --git a/sorting/bucket_sort.rb b/sorting/bucket_sort.rb
index 213d142..eb55b94 100644
--- a/sorting/bucket_sort.rb
+++ b/sorting/bucket_sort.rb
@@ -1,30 +1,29 @@
-
-DEFAULT_BUCKET_SIZE = 5
-
-def bucket_sort(input, bucket_size = DEFAULT_BUCKET_SIZE)
-  print 'Array is empty' if input.empty?
-
-  array = input.split(' ').map(&:to_i)
-
-  bucket_count = ((array.max - array.min) / bucket_size).floor + 1
-
-  # create buckets
-  buckets = []
-  bucket_count.times { buckets.push [] }
-
-  # fill buckets
-  array.each do |item|
-    buckets[((item - array.min) / bucket_size).floor].push(item)
-  end
-
-  # sort buckets
-  buckets.each do |bucket|
-    bucket.sort!
-  end
-
-  buckets.flatten.join(' ')
-end
-puts "Enter a list of numbers separated by space"
-
-list = gets
-print bucket_sort(list)
+DEFAULT_BUCKET_SIZE = 5
+
+def bucket_sort(input, bucket_size = DEFAULT_BUCKET_SIZE)
+  print 'Array is empty' if input.empty?
+
+  array = input.split(' ').map(&:to_i)
+
+  bucket_count = ((array.max - array.min) / bucket_size).floor + 1
+
+  # create buckets
+  buckets = []
+  bucket_count.times { buckets.push [] }
+
+  # fill buckets
+  array.each do |item|
+    buckets[((item - array.min) / bucket_size).floor].push(item)
+  end
+
+  # sort buckets
+  buckets.each do |bucket|
+    bucket.sort!
+  end
+
+  buckets.flatten.join(' ')
+end
+puts 'Enter a list of numbers separated by space'
+
+list = gets
+print bucket_sort(list)
diff --git a/sorting/heap_sort.rb b/sorting/heap_sort.rb
index 9b527f7..40f9a08 100644
--- a/sorting/heap_sort.rb
+++ b/sorting/heap_sort.rb
@@ -7,25 +7,26 @@ def heap_sort(array)
     adjusted_down(adjusted_array, i, array_size)
   end
   while array_size > 1
-    adjusted_array[1], adjusted_array[array_size] = adjusted_array[array_size], adjusted_array[1]  
+    adjusted_array[1], adjusted_array[array_size] = adjusted_array[array_size], adjusted_array[1]
     array_size -= 1
     adjusted_down(adjusted_array, 1, array_size)
   end
   adjusted_array.drop(1)
 end
 
-#Method to adjust heap in downward manner
+# Method to adjust heap in downward manner
 def adjusted_down(adjusted_array, parent, limit)
   top = adjusted_array[parent]
   while (child = 2 * parent) <= limit
-    child += 1  if child < limit and adjusted_array[child] < adjusted_array[child + 1]  
-    break  if top >= adjusted_array[child]
+    child += 1 if (child < limit) && (adjusted_array[child] < adjusted_array[child + 1])
+    break if top >= adjusted_array[child]
+
     adjusted_array[parent] = adjusted_array[child]
     parent = child
   end
   adjusted_array[parent] = top
 end
 
-#Code for testing heapsort
+# Code for testing heapsort
 array = [1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15].shuffle
-print heap_sort(array)
\ No newline at end of file
+print heap_sort(array)
diff --git a/sorting/insertion_sort.rb b/sorting/insertion_sort.rb
index 2151089..120a0f4 100644
--- a/sorting/insertion_sort.rb
+++ b/sorting/insertion_sort.rb
@@ -1,17 +1,17 @@
-def insertion_sort(array)
-  0.upto(array.length - 1).each do |index|
-    element = array[index]
-    position = index
-    while element < array[position - 1] && position > 0
-      array[position] = array[position - 1]
-      array[position - 1] = element
-      position -= 1
-    end
-  end
-  array
-end
-puts "Enter a list of numbers separated by space"
-
-list = gets
-insertion_sort(list)
-print list
\ No newline at end of file
+def insertion_sort(array)
+  0.upto(array.length - 1).each do |index|
+    element = array[index]
+    position = index
+    while element < array[position - 1] && position > 0
+      array[position] = array[position - 1]
+      array[position - 1] = element
+      position -= 1
+    end
+  end
+  array
+end
+puts 'Enter a list of numbers separated by space'
+
+list = gets
+insertion_sort(list)
+print list
diff --git a/sorting/merge_sort.rb b/sorting/merge_sort.rb
index 87f11f0..16dc298 100644
--- a/sorting/merge_sort.rb
+++ b/sorting/merge_sort.rb
@@ -1,5 +1,6 @@
 def merge_sort(array)
   return array if array.length <= 1
+
   mid = array.length / 2
   first_array = array.slice(0..mid - 1)
   second_array = array.slice(mid..-1)
@@ -9,7 +10,7 @@ def merge_sort(array)
 
   # merge
   result = []
-  until first_array.empty? and second_array.empty?
+  until first_array.empty? && second_array.empty?
     if first_array.empty?
       result.concat(second_array)
       second_array.clear
@@ -17,16 +18,16 @@ def merge_sort(array)
       result.concat(first_array)
       first_array.clear
     else
-      if first_array.first < second_array.first
-        result << first_array.shift
-      else
-        result << second_array.shift
-      end
+      result << if first_array.first < second_array.first
+                  first_array.shift
+                else
+                  second_array.shift
+                end
     end
   end
   result
 end
 
-puts "Enter a list of numbers separated by space"
+puts 'Enter a list of numbers separated by space'
 list = gets
-print merge_sort list.split(" ").map(&:to_i)
+print merge_sort list.split(' ').map(&:to_i)
diff --git a/sorting/quicksort.rb b/sorting/quicksort.rb
index cb801d0..24249f6 100644
--- a/sorting/quicksort.rb
+++ b/sorting/quicksort.rb
@@ -8,7 +8,7 @@ def quicksort(arr)
   left, right = arr.partition(&pivot.method(:>))
 
   # recursively calling the quicksort method on itself
-  return *quicksort(left), pivot, *quicksort(right)
+  [*quicksort(left), pivot, *quicksort(right)]
 end
 
 arr = [34, 2, 1, 5, 3]
diff --git a/sorting/selection_sort.rb b/sorting/selection_sort.rb
index 3314ead..b32c944 100644
--- a/sorting/selection_sort.rb
+++ b/sorting/selection_sort.rb
@@ -13,6 +13,6 @@ def selection_sort(array)
   end
 end
 
-arr = ([9,8,3,1,2,55,68,48].shuffle) #We have taken a rondom example and also shuffling it
+arr = [9, 8, 3, 1, 2, 55, 68, 48].shuffle # We have taken a rondom example and also shuffling it
 selection_sort(arr)
 puts "Sorted array is: #{arr.inspect}"
diff --git a/sorting/shell_sort.rb b/sorting/shell_sort.rb
index 7cbdea8..e6167f5 100644
--- a/sorting/shell_sort.rb
+++ b/sorting/shell_sort.rb
@@ -1,27 +1,24 @@
 def shell_sort(a)
-  n=a.length
-  h=1
+  n = a.length
+  h = 1
 
-  while (h<n/3)  #for computing increment factor "h"
-    h= (3*h)+1
-  end
+  h = (3 * h) + 1 while h < n / 3
 
-  while h>=1
+  while h >= 1
     # Logic of insertion sort with inrement steps of "h"
-    for i in h...n
-      j=i
-      while j>=h
-        if a[j-h]>a[j]
-          temp=a[j]
-          a[j]=a[j-h]
-          a[j-h]=temp
+    (h...n).each do |i|
+      j = i
+      while j >= h
+        if a[j - h] > a[j]
+          temp = a[j]
+          a[j] = a[j - h]
+          a[j - h] = temp
         end
-        j-=h
+        j -= h
       end
     end
-    h/=3
+    h /= 3
   end
 
-  return a
-
+  a
 end