Merge pull request #672 from fartem/48_Rotate_Image

2024-07-15 v. 6.1.5: added "48. Rotate Image"

Author: fartem

README.md

@@ -480,3 +480,4 @@ Profile on LeetCode: [fartem](https://leetcode.com/fartem/).
 | 39. Combination Sum                                         | [Link](https://leetcode.com/problems/combination-sum/)                                         | [Link](./lib/medium/39_combination_sum.rb)                                         |
 | 43. Multiply Strings                                        | [Link](https://leetcode.com/problems/multiply-strings/)                                        | [Link](./lib/medium/43_multiply_strings.rb)                                        |
 | 46. Permutations                                            | [Link](https://leetcode.com/problems/permutations/)                                            | [Link](./lib/medium/46_permutations.rb)                                            |
+| 48. Rotate Image                                            | [Link](https://leetcode.com/problems/rotate-image/)                                            | [Link](./lib/medium/48_rotate_image.rb)                                            |

leetcode-ruby.gemspec

@@ -5,7 +5,7 @@ require 'English'
 ::Gem::Specification.new do |s|
   s.required_ruby_version = '>= 3.0'
   s.name = 'leetcode-ruby'
-  s.version = '6.1.4'
+  s.version = '6.1.5'
   s.license = 'MIT'
   s.files = ::Dir['lib/**/*.rb'] + %w[bin/leetcode-ruby README.md LICENSE]
   s.executable = 'leetcode-ruby'

lib/medium/48_rotate_image.rb

@@ -0,0 +1,24 @@
+# frozen_string_literal: true
+
+# https://leetcode.com/problems/rotate-image/
+# @param {Integer[][]} matrix
+# @return {Void} Do not return anything, modify matrix in-place instead.
+def rotate(matrix)
+  n = matrix.length
+  up = (n + 1) / 2
+
+  (0...up).each do |i|
+    h = n / 2
+
+    (0...h).each do |j|
+      f_index = n - j - 1
+      temp = matrix[f_index][i]
+      s_index = n - i - 1
+
+      matrix[f_index][i] = matrix[s_index][f_index]
+      matrix[s_index][f_index] = matrix[j][s_index]
+      matrix[j][s_index] = matrix[i][j]
+      matrix[i][j] = temp
+    end
+  end
+end

test/medium/test_48_rotate_image.rb

@@ -0,0 +1,43 @@
+# frozen_string_literal: true
+
+require_relative '../test_helper'
+require_relative '../../lib/medium/48_rotate_image'
+require 'minitest/autorun'
+
+class RotateImageTest < ::Minitest::Test
+  def test_default
+    matrix = [
+      [1, 2, 3],
+      [4, 5, 6],
+      [7, 8, 9]
+    ]
+    rotate(matrix)
+
+    assert_equal(
+      [
+        [7, 4, 1],
+        [8, 5, 2],
+        [9, 6, 3]
+      ],
+      matrix
+    )
+
+    matrix = [
+      [5, 1, 9, 11],
+      [2, 4, 8, 10],
+      [13, 3, 6, 7],
+      [15, 14, 12, 16]
+    ]
+    rotate(matrix)
+
+    assert_equal(
+      [
+        [15, 13, 2, 5],
+        [14, 3, 4, 1],
+        [12, 6, 8, 9],
+        [16, 7, 10, 11]
+      ],
+      matrix
+    )
+  end
+end