36

Author: TedTran2019

ruby/36-Valid-Sudoku.rb

@@ -0,0 +1,48 @@
+def is_valid_sudoku(board)
+  valid_rows_and_columns?(board) && valid_boxes?(board)
+end
+
+def valid_rows_and_columns?(board)
+  (0...9).each do |y|
+    column = []
+    row = []
+    (0...9).each do |x|
+      row << board[y][x]
+      column << board[x][y]
+    end
+    return false unless valid?(row) && valid?(column)
+  end
+  true
+end
+
+def valid?(row)
+  hash = {}
+  row.each do |cell|
+    next if cell == '.'
+    return false if hash.key? cell
+
+    hash[cell] = true
+  end
+
+  true
+end
+
+def valid_boxes?(board)
+  y_cap = 0
+  until y_cap == 9
+    x_cap = 0
+    until x_cap == 9
+      box = []
+      (y_cap...(y_cap + 3)).each do |y|
+        (x_cap...(x_cap + 3)).each do |x|
+          box << board[y][x]
+        end
+        return false unless valid?(box)
+      end
+      x_cap += 3
+    end
+    y_cap += 3
+  end
+
+  true
+end