2024-07-09 v. 6.1.0: added "36. Valid Sudoku"

Author: fartem

README.md

@@ -475,3 +475,4 @@ Profile on LeetCode: [fartem](https://leetcode.com/fartem/).
 | 29. Divide Two Integers                                     | [Link](https://leetcode.com/problems/divide-two-integers/)                                     | [Link](./lib/medium/29_divide_two_integers.rb)                                     |
 | 33. Search in Rotated Sorted Array                          | [Link](https://leetcode.com/problems/search-in-rotated-sorted-array/)                          | [Link](./lib/medium/33_search_in_rotated_sorted_array.rb)                          |
 | 34. Find First and Last Position of Element in Sorted Array | [Link](https://leetcode.com/problems/find-first-and-last-position-of-element-in-sorted-array/) | [Link](./lib/medium/34_find_first_and_last_position_of_element_in_sorted_array.rb) |
+| 36. Valid Sudoku                                            | [Link](https://leetcode.com/problems/valid-sudoku/)                                            | [Link](./lib/medium/36_valid_sudoku.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 = '6.0.9'
+  s.version = '6.1.0'
   s.license = 'MIT'
   s.files = ::Dir['lib/**/*.rb'] + %w[bin/leetcode-ruby README.md LICENSE]
   s.executable = 'leetcode-ruby'

lib/medium/36_valid_sudoku.rb

@@ -0,0 +1,72 @@
+# frozen_string_literal: true
+
+# https://leetcode.com/problems/valid-sudoku/
+# @param {Character[][]} board
+# @return {Boolean}
+def is_valid_sudoku(board)
+  [
+    has_valid_rows?(board),
+    has_valid_columns?(board),
+    has_valid_grids?(board)
+  ].all?
+end
+
+private
+
+# @param {Character[][]} board
+# @return {Boolean}
+def has_valid_rows?(board)
+  board.all? { |row| is_valid_array?(row) }
+end
+
+# @param {Character[]} arr
+# @return {Boolean}
+def is_valid_array?(arr)
+  ref = [0] * 10
+
+  arr.each do |sq|
+    next if sq == '.'
+
+    num = sq.to_i
+
+    return false if num.zero? || num > 9 || ref[num] == 1
+
+    ref[num] = 1
+  end
+end
+
+# @param {Character[][]} board
+# @return {Boolean}
+def has_valid_columns?(board)
+  (0...9).each do |n|
+    column = board.map { |row| row[n] }
+
+    return false unless is_valid_array?(column)
+  end
+
+  true
+end
+
+# @param {Character[][]} board
+# @return {Boolean}
+def has_valid_grids?(board)
+  [0, 3, 6].each do |i|
+    [0, 3, 6].each do |j|
+      grid = [
+        board[i][j],
+        board[i][j + 1],
+        board[i][j + 2],
+        board[i + 1][j],
+        board[i + 1][j + 1],
+        board[i + 1][j + 2],
+        board[i + 2][j],
+        board[i + 2][j + 1],
+        board[i + 2][j + 2]
+      ]
+
+      return false unless is_valid_array?(grid)
+    end
+  end
+
+  true
+end

test/medium/test_36_valid_sudoku.rb

@@ -0,0 +1,40 @@
+# frozen_string_literal: true
+
+require_relative '../test_helper'
+require_relative '../../lib/medium/36_valid_sudoku'
+require 'minitest/autorun'
+
+class ValidSudokuTest < ::Minitest::Test
+  def test_default
+    assert(
+      is_valid_sudoku(
+        [
+          %w[5 3 . . 7 . . . .],
+          %w[6 . . 1 9 5 . . .],
+          %w[. 9 8 . . . . 6 .],
+          %w[8 . . . 6 . . . 3],
+          %w[4 . . 8 . 3 . . 1],
+          %w[7 . . . 2 . . . 6],
+          %w[. 6 . . . . 2 8 .],
+          %w[. . . 4 1 9 . . 5],
+          %w[. . . . 8 . . 7 9]
+        ]
+      )
+    )
+    assert(
+      !is_valid_sudoku(
+        [
+          %w[8 3 . . 7 . . . .],
+          %w[6 . . 1 9 5 . . .],
+          %w[. 9 8 . . . . 6 .],
+          %w[8 . . . 6 . . . 3],
+          %w[4 . . 8 . 3 . . 1],
+          %w[7 . . . 2 . . . 6],
+          %w[. 6 . . . . 2 8 .],
+          %w[. . . 4 1 9 . . 5],
+          %w[. . . . 8 . . 7 9]
+        ]
+      )
+    )
+  end
+end