From 989e20d15ee85cbbc372c79801d17a4a44733bef Mon Sep 17 00:00:00 2001
From: Jessica Kwok <jessicatckwok@gmail.com>
Date: Mon, 22 Mar 2021 09:00:58 -0700
Subject: [PATCH 1/4] Add shuffle array challenge

---
 DIRECTORY.md                            |  1 +
 data_structures/arrays/shuffle_array.rb | 36 +++++++++++++++++++++++++
 2 files changed, 37 insertions(+)
 create mode 100644 data_structures/arrays/shuffle_array.rb

diff --git a/DIRECTORY.md b/DIRECTORY.md
index 5983249..4eb3612 100644
--- a/DIRECTORY.md
+++ b/DIRECTORY.md
@@ -13,6 +13,7 @@
     * [Fizz Buzz](https://github.com/TheAlgorithms/Ruby/blob/master/data_structures/arrays/fizz_buzz.rb)
     * [Get Products Of All Other Elements](https://github.com/TheAlgorithms/Ruby/blob/master/data_structures/arrays/get_products_of_all_other_elements.rb)
     * [Remove Elements](https://github.com/TheAlgorithms/Ruby/blob/master/data_structures/arrays/remove_elements.rb)
+    * [Shuffle Array](https://github.com/TheAlgorithms/Ruby/blob/master/data_structures/arrays/shuffle_array.rb)
     * [Sort Squares Of An Array](https://github.com/TheAlgorithms/Ruby/blob/master/data_structures/arrays/sort_squares_of_an_array.rb)
     * [Two Sum](https://github.com/TheAlgorithms/Ruby/blob/master/data_structures/arrays/two_sum.rb)
     * [Two Sum Ii](https://github.com/TheAlgorithms/Ruby/blob/master/data_structures/arrays/two_sum_ii.rb)
diff --git a/data_structures/arrays/shuffle_array.rb b/data_structures/arrays/shuffle_array.rb
new file mode 100644
index 0000000..93efa84
--- /dev/null
+++ b/data_structures/arrays/shuffle_array.rb
@@ -0,0 +1,36 @@
+# Challenge name: Shuffle the array
+# Given the array nums consisting of 2n elements
+# in the form [x1,x2,...,xn,y1,y2,...,yn].
+# Return the array in the form [x1,y1,x2,y2,...,xn,yn].
+# Example 1:
+#
+# Input: nums = [2,5,1,3,4,7], n = 3
+# Output: [2,3,5,4,1,7]
+# Explanation: Since x1=2, x2=5, x3=1, y1=3, y2=4, y3=7 then the answer is [2,3,5,4,1,7].
+#
+# Example 2:
+#
+# Input: nums = [1,2,3,4,4,3,2,1], n = 4
+# Output: [1,4,2,3,3,2,4,1]
+#
+# Example 3:
+#
+# Input: nums = [1,1,2,2], n = 2
+# Output: [1,2,1,2]
+# @param {Integer[]} nums
+# @param {Integer} n
+# @return {Integer[]}
+def shuffle(nums, n)
+end
+nums = [2, 5, 1, 3, 4, 7]
+n = 3
+print(shuffle(nums, n))
+# Output: [2,3,5,4,1,7]
+nums = [1, 2, 3, 4, 4, 3, 2, 1]
+n = 4
+print(shuffle(nums, n))
+# Output: [1,4,2,3,3,2,4,1]
+nums = [1, 1, 2, 2]
+n = 2
+print(shuffle(nums, n))
+# Output: [1,2,1,2]
\ No newline at end of file

From 16fd8c756ff5508c611bf42173a9fc998c3f5e8e Mon Sep 17 00:00:00 2001
From: Jessica Kwok <jessicatckwok@gmail.com>
Date: Tue, 23 Mar 2021 08:42:36 -0700
Subject: [PATCH 2/4] Add solution using a new array

---
 data_structures/arrays/shuffle_array.rb | 18 +++++++++++++++---
 1 file changed, 15 insertions(+), 3 deletions(-)

diff --git a/data_structures/arrays/shuffle_array.rb b/data_structures/arrays/shuffle_array.rb
index 93efa84..b4c6431 100644
--- a/data_structures/arrays/shuffle_array.rb
+++ b/data_structures/arrays/shuffle_array.rb
@@ -1,27 +1,39 @@
 # Challenge name: Shuffle the array
+#
 # Given the array nums consisting of 2n elements
 # in the form [x1,x2,...,xn,y1,y2,...,yn].
 # Return the array in the form [x1,y1,x2,y2,...,xn,yn].
-# Example 1:
 #
+# Example 1:
 # Input: nums = [2,5,1,3,4,7], n = 3
 # Output: [2,3,5,4,1,7]
 # Explanation: Since x1=2, x2=5, x3=1, y1=3, y2=4, y3=7 then the answer is [2,3,5,4,1,7].
 #
 # Example 2:
-#
 # Input: nums = [1,2,3,4,4,3,2,1], n = 4
 # Output: [1,4,2,3,3,2,4,1]
 #
 # Example 3:
-#
 # Input: nums = [1,1,2,2], n = 2
 # Output: [1,2,1,2]
+#
 # @param {Integer[]} nums
 # @param {Integer} n
 # @return {Integer[]}
+
+#
+# Approach 1: New Array
+#
+# Time Complexity: O(N)
+#
 def shuffle(nums, n)
+  result = []
+  (0..n-1).count do |i|
+    result.push(nums[i], nums[i+n])
+  end
+  result
 end
+
 nums = [2, 5, 1, 3, 4, 7]
 n = 3
 print(shuffle(nums, n))

From a8f816f984ad98f59942aae06eff775816bf83f8 Mon Sep 17 00:00:00 2001
From: Jessica Kwok <jessicatckwok@gmail.com>
Date: Wed, 24 Mar 2021 08:12:31 -0700
Subject: [PATCH 3/4] Add solution using Ruby methods

---
 data_structures/arrays/shuffle_array.rb | 28 +++++++++++++++++++++++++
 1 file changed, 28 insertions(+)

diff --git a/data_structures/arrays/shuffle_array.rb b/data_structures/arrays/shuffle_array.rb
index b4c6431..2f1b13f 100644
--- a/data_structures/arrays/shuffle_array.rb
+++ b/data_structures/arrays/shuffle_array.rb
@@ -34,6 +34,34 @@ def shuffle(nums, n)
   result
 end
 
+# nums = [2, 5, 1, 3, 4, 7]
+# n = 3
+# print(shuffle(nums, n))
+# # Output: [2,3,5,4,1,7]
+# nums = [1, 2, 3, 4, 4, 3, 2, 1]
+# n = 4
+# print(shuffle(nums, n))
+# # Output: [1,4,2,3,3,2,4,1]
+# nums = [1, 1, 2, 2]
+# n = 2
+# print(shuffle(nums, n))
+# # Output: [1,2,1,2]
+
+#
+# Approach 2: Use Ruby methods .insert() and .delete_at()
+#
+# Time Complexity: O(N)
+#
+
+def shuffle(nums, n)
+  current_index = 1
+  (0..n-1).each do |i|
+    nums.insert(current_index, nums.delete_at(i + n))
+    current_index += 2
+  end
+  nums
+end
+
 nums = [2, 5, 1, 3, 4, 7]
 n = 3
 print(shuffle(nums, n))

From ad685ac4ee922161ba193a13050e38f3f050825d Mon Sep 17 00:00:00 2001
From: Jessica Kwok <jessicatckwok@gmail.com>
Date: Mon, 29 Mar 2021 10:22:09 -0700
Subject: [PATCH 4/4] Add two pointers approach

---
 data_structures/arrays/shuffle_array.rb | 57 +++++++++++++++++++------
 1 file changed, 45 insertions(+), 12 deletions(-)

diff --git a/data_structures/arrays/shuffle_array.rb b/data_structures/arrays/shuffle_array.rb
index 2f1b13f..22ec07a 100644
--- a/data_structures/arrays/shuffle_array.rb
+++ b/data_structures/arrays/shuffle_array.rb
@@ -34,18 +34,18 @@ def shuffle(nums, n)
   result
 end
 
-# nums = [2, 5, 1, 3, 4, 7]
-# n = 3
-# print(shuffle(nums, n))
-# # Output: [2,3,5,4,1,7]
-# nums = [1, 2, 3, 4, 4, 3, 2, 1]
-# n = 4
-# print(shuffle(nums, n))
-# # Output: [1,4,2,3,3,2,4,1]
-# nums = [1, 1, 2, 2]
-# n = 2
-# print(shuffle(nums, n))
-# # Output: [1,2,1,2]
+nums = [2, 5, 1, 3, 4, 7]
+n = 3
+print(shuffle(nums, n))
+# Output: [2,3,5,4,1,7]
+nums = [1, 2, 3, 4, 4, 3, 2, 1]
+n = 4
+print(shuffle(nums, n))
+# Output: [1,4,2,3,3,2,4,1]
+nums = [1, 1, 2, 2]
+n = 2
+print(shuffle(nums, n))
+# Output: [1,2,1,2]
 
 #
 # Approach 2: Use Ruby methods .insert() and .delete_at()
@@ -62,6 +62,39 @@ def shuffle(nums, n)
   nums
 end
 
+nums = [2, 5, 1, 3, 4, 7]
+n = 3
+print(shuffle(nums, n))
+# Output: [2,3,5,4,1,7]
+nums = [1, 2, 3, 4, 4, 3, 2, 1]
+n = 4
+print(shuffle(nums, n))
+# Output: [1,4,2,3,3,2,4,1]
+nums = [1, 1, 2, 2]
+n = 2
+print(shuffle(nums, n))
+# Output: [1,2,1,2]
+
+#
+# Approach 3: Two Pointers
+#
+# Time Complexity: O(N)
+#
+
+def shuffle(nums, n)
+  result = []
+  p1 = 0
+  p2 = n
+
+  while p1 < n
+    result.push(nums[p1], nums[p2])
+    p1 +=1
+    p2 +=1
+  end
+
+  result
+end
+
 nums = [2, 5, 1, 3, 4, 7]
 n = 3
 print(shuffle(nums, n))