From c8b91b82221f3164baa09d21c00fa7c28498ae3a Mon Sep 17 00:00:00 2001
From: Vitor Oliveira <vbrazo@gmail.com>
Date: Tue, 8 Jun 2021 11:27:59 -0700
Subject: [PATCH 1/7] Add dynamic programming approach 1

---
 dynamic_programming/pascal_triangle_ii.rb | 53 +++++++++++++++++++++++
 1 file changed, 53 insertions(+)
 create mode 100644 dynamic_programming/pascal_triangle_ii.rb

diff --git a/dynamic_programming/pascal_triangle_ii.rb b/dynamic_programming/pascal_triangle_ii.rb
new file mode 100644
index 0000000..564840b
--- /dev/null
+++ b/dynamic_programming/pascal_triangle_ii.rb
@@ -0,0 +1,53 @@
+# Challenge name: Pascal's triangle ii
+#
+# Given an integer row_index, return the rowIndexth (0-indexed) row of the Pascal's triangle.
+# Example 1:
+#
+# Input: row_index = 3
+# Output: [1,3,3,1]
+#
+# Example 2:
+#
+# Input: row_index = 0
+# Output: [1]
+#
+# Example 3:
+#
+# Input: row_index = 1
+# Output: [1,1]
+
+#
+# Approach 1: Dynamic Programming
+#
+
+# Complexity Analysis
+#
+# Time complexity: O(k^2).
+# Space complexity: O(k) + O(k) ~ O(k).
+
+# @param {Integer} row_index
+# @return {Integer[]}
+def get_row(row_index)
+  result = generate(row_index)
+  result[result.count - 1]
+end
+
+def generate(num_rows)
+  return [[1]] if num_rows < 1
+  result = [[1], [1, 1]]
+
+  (2...num_rows + 1).each do |row|
+    prev = result[row - 1]
+    current = [1]
+    med = prev.count / 2
+
+    (1...prev.count).each do |i|
+      current[i] = prev[i - 1] + prev[i]
+    end
+
+    current.push(1)
+    result.push(current)
+  end
+
+  result
+end

From a0af18e002445a6925995ab6c7b277a13efab5b7 Mon Sep 17 00:00:00 2001
From: Vitor Oliveira <vbrazo@gmail.com>
Date: Tue, 8 Jun 2021 11:28:05 -0700
Subject: [PATCH 2/7] Add dynamic programming approach 2

---
 dynamic_programming/pascal_triangle_ii.rb | 38 +++++++++++++++++++++++
 1 file changed, 38 insertions(+)

diff --git a/dynamic_programming/pascal_triangle_ii.rb b/dynamic_programming/pascal_triangle_ii.rb
index 564840b..837d2f0 100644
--- a/dynamic_programming/pascal_triangle_ii.rb
+++ b/dynamic_programming/pascal_triangle_ii.rb
@@ -51,3 +51,41 @@ def generate(num_rows)
 
   result
 end
+
+#
+# Approach 2: Memory-efficient Dynamic Programming
+#
+
+# Complexity Analysis
+#
+# Time complexity: O(k^2).
+# Space complexity: O(k).
+
+# @param {Integer} row_index
+# @return {Integer[]}
+def get_row(row_index)
+  pascal = [[1]]
+
+  (1..row_index).each do |i|
+    pascal[i] = []
+    pascal[i][0] = pascal[i][i] = 1
+
+    (1...i).each do |j|
+      pascal[i][j] = pascal[i - 1][j - 1] + pascal[i - 1][j]
+    end
+  end
+
+  pascal[row_index]
+end
+
+row_index = 3
+print(get_row(row_index))
+# => [1,3,3,1]
+
+row_index = 0
+print(get_row(row_index))
+# => [1]
+
+row_index = 1
+print(get_row(row_index))
+# => [1,1]

From e202d15e6b4720e8f1d64893cf764ea29c86b5e9 Mon Sep 17 00:00:00 2001
From: github-actions <${GITHUB_ACTOR}@users.noreply.github.com>
Date: Tue, 8 Jun 2021 18:28:22 +0000
Subject: [PATCH 3/7] updating DIRECTORY.md

---
 DIRECTORY.md | 1 +
 1 file changed, 1 insertion(+)

diff --git a/DIRECTORY.md b/DIRECTORY.md
index 6babc0a..8f75d7c 100644
--- a/DIRECTORY.md
+++ b/DIRECTORY.md
@@ -78,6 +78,7 @@
   * [Coin Change](https://github.com/TheAlgorithms/Ruby/blob/master/dynamic_programming/coin_change.rb)
   * [Count Sorted Vowel Strings](https://github.com/TheAlgorithms/Ruby/blob/master/dynamic_programming/count_sorted_vowel_strings.rb)
   * [Fibonacci](https://github.com/TheAlgorithms/Ruby/blob/master/dynamic_programming/fibonacci.rb)
+  * [Pascal Triangle Ii](https://github.com/TheAlgorithms/Ruby/blob/master/dynamic_programming/pascal_triangle_ii.rb)
 
 ## Maths
   * [Abs](https://github.com/TheAlgorithms/Ruby/blob/master/maths/abs.rb)

From 130e736aa66944070def5598910ab2c6a1bf3f1d Mon Sep 17 00:00:00 2001
From: Vitor Oliveira <vbrazo@gmail.com>
Date: Tue, 8 Jun 2021 11:28:22 -0700
Subject: [PATCH 4/7] minor changes

---
 dynamic_programming/pascal_triangle_ii.rb | 2 --
 1 file changed, 2 deletions(-)

diff --git a/dynamic_programming/pascal_triangle_ii.rb b/dynamic_programming/pascal_triangle_ii.rb
index 837d2f0..761f0c1 100644
--- a/dynamic_programming/pascal_triangle_ii.rb
+++ b/dynamic_programming/pascal_triangle_ii.rb
@@ -1,5 +1,3 @@
-# Challenge name: Pascal's triangle ii
-#
 # Given an integer row_index, return the rowIndexth (0-indexed) row of the Pascal's triangle.
 # Example 1:
 #

From c7329e6bf40447088db04953a50cb43be6c2d6fd Mon Sep 17 00:00:00 2001
From: Vitor Oliveira <vbrazo@gmail.com>
Date: Tue, 8 Jun 2021 11:30:08 -0700
Subject: [PATCH 5/7] add brute force approach

---
 dynamic_programming/pascal_triangle_ii.rb | 34 +++++++++++++++++++++--
 1 file changed, 32 insertions(+), 2 deletions(-)

diff --git a/dynamic_programming/pascal_triangle_ii.rb b/dynamic_programming/pascal_triangle_ii.rb
index 761f0c1..17119aa 100644
--- a/dynamic_programming/pascal_triangle_ii.rb
+++ b/dynamic_programming/pascal_triangle_ii.rb
@@ -15,7 +15,37 @@
 # Output: [1,1]
 
 #
-# Approach 1: Dynamic Programming
+# Approach 1: Brute Force
+#
+
+# Complexity Analysis
+#
+# Time complexity: O(k^2).
+# Space complexity: O(k) + O(k) ~ O(k)
+
+def get_num(row, col)
+  return 1 if row == 0 || col == 0 || row == col
+  get_num(row - 1, col - 1) + get_num(row - 1, col)
+end
+def get_row(row_index)
+  result = []
+  (row_index + 1).times do |i|
+    result.push(get_num(row_index, i))
+  end
+  result
+end
+row_index = 3
+print(get_row(row_index))
+# => [1,3,3,1]
+row_index = 0
+print(get_row(row_index))
+# => [1]
+row_index = 1
+print(get_row(row_index))
+# => [1,1]
+
+#
+# Approach 2: Dynamic Programming
 #
 
 # Complexity Analysis
@@ -51,7 +81,7 @@ def generate(num_rows)
 end
 
 #
-# Approach 2: Memory-efficient Dynamic Programming
+# Approach 3: Memory-efficient Dynamic Programming
 #
 
 # Complexity Analysis

From b4d5726791d375ad8388b741793f6843b8ea73a2 Mon Sep 17 00:00:00 2001
From: Vitor Oliveira <vbrazo@gmail.com>
Date: Tue, 8 Jun 2021 11:36:07 -0700
Subject: [PATCH 6/7] add enter

---
 dynamic_programming/pascal_triangle_ii.rb | 7 +++++++
 1 file changed, 7 insertions(+)

diff --git a/dynamic_programming/pascal_triangle_ii.rb b/dynamic_programming/pascal_triangle_ii.rb
index 17119aa..568e76d 100644
--- a/dynamic_programming/pascal_triangle_ii.rb
+++ b/dynamic_programming/pascal_triangle_ii.rb
@@ -25,21 +25,28 @@
 
 def get_num(row, col)
   return 1 if row == 0 || col == 0 || row == col
+
   get_num(row - 1, col - 1) + get_num(row - 1, col)
 end
+
 def get_row(row_index)
   result = []
+
   (row_index + 1).times do |i|
     result.push(get_num(row_index, i))
   end
+
   result
 end
+
 row_index = 3
 print(get_row(row_index))
 # => [1,3,3,1]
+
 row_index = 0
 print(get_row(row_index))
 # => [1]
+
 row_index = 1
 print(get_row(row_index))
 # => [1,1]

From 6defd7eab5775857171589a8ee54d3c6bd7b8957 Mon Sep 17 00:00:00 2001
From: Vitor Oliveira <vbrazo@gmail.com>
Date: Tue, 8 Jun 2021 11:42:17 -0700
Subject: [PATCH 7/7] add missing output

---
 dynamic_programming/pascal_triangle_ii.rb | 12 ++++++++++++
 1 file changed, 12 insertions(+)

diff --git a/dynamic_programming/pascal_triangle_ii.rb b/dynamic_programming/pascal_triangle_ii.rb
index 568e76d..f9e73f3 100644
--- a/dynamic_programming/pascal_triangle_ii.rb
+++ b/dynamic_programming/pascal_triangle_ii.rb
@@ -87,6 +87,18 @@ def generate(num_rows)
   result
 end
 
+row_index = 3
+print(get_row(row_index))
+# => [1,3,3,1]
+
+row_index = 0
+print(get_row(row_index))
+# => [1]
+
+row_index = 1
+print(get_row(row_index))
+# => [1,1]
+
 #
 # Approach 3: Memory-efficient Dynamic Programming
 #