Commit fcabb68

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+<<-DOC
+Sudoku is a number-placement puzzle. The objective is to fill a 9 × 9 grid with numbers in such a way that each column, each row, and each of the nine 3 × 3 sub-grids that compose the grid all contain all of the numbers from 1 to 9 one time.
+
+Implement an algorithm that will check whether the given grid of numbers represents a valid Sudoku puzzle according to the layout rules described above. Note that the puzzle represented by grid does not have to be solvable.
+
+Example
+
+For
+
+grid = [['.', '.', '.', '1', '4', '.', '.', '2', '.'],
+        ['.', '.', '6', '.', '.', '.', '.', '.', '.'],
+        ['.', '.', '.', '.', '.', '.', '.', '.', '.'],
+        ['.', '.', '1', '.', '.', '.', '.', '.', '.'],
+        ['.', '6', '7', '.', '.', '.', '.', '.', '9'],
+        ['.', '.', '.', '.', '.', '.', '8', '1', '.'],
+        ['.', '3', '.', '.', '.', '.', '.', '.', '6'],
+        ['.', '.', '.', '.', '.', '7', '.', '.', '.'],
+        ['.', '.', '.', '5', '.', '.', '.', '7', '.']]
+the output should be
+sudoku2(grid) = true;
+
+For
+
+grid = [['.', '.', '.', '.', '2', '.', '.', '9', '.'],
+        ['.', '.', '.', '.', '6', '.', '.', '.', '.'],
+        ['7', '1', '.', '.', '7', '5', '.', '.', '.'],
+        ['.', '7', '.', '.', '.', '.', '.', '.', '.'],
+        ['.', '.', '.', '.', '8', '3', '.', '.', '.'],
+        ['.', '.', '8', '.', '.', '7', '.', '6', '.'],
+        ['.', '.', '.', '.', '.', '2', '.', '.', '.'],
+        ['.', '1', '.', '2', '.', '.', '.', '.', '.'],
+        ['.', '2', '.', '.', '3', '.', '.', '.', '.']]
+the output should be
+sudoku2(grid) = false.
+
+The given grid is not correct because there are two 1s in the second column. Each column, each row, and each 3 × 3 subgrid can only contain the numbers 1 through 9 one time.
+
+Input/Output
+
+[time limit] 4000ms (rb)
+[input] array.array.char grid
+
+A 9 × 9 array of characters, in which each character is either a digit from '1' to '9' or a period '.'.
+
+[output] boolean
+
+Return true if grid represents a valid Sudoku puzzle, otherwise return false.
+DOC
+describe "sudoku2" do
+  def sudoku2(grid)
+  end
+
+  [
+    { grid: [[".",".",".","1","4",".",".","2","."], [".",".","6",".",".",".",".",".","."], [".",".",".",".",".",".",".",".","."], [".",".","1",".",".",".",".",".","."], [".","6","7",".",".",".",".",".","9"], [".",".",".",".",".",".","8","1","."], [".","3",".",".",".",".",".",".","6"], [".",".",".",".",".","7",".",".","."], [".",".",".","5",".",".",".","7","."]], expected: true },
+  ].each do |x|
+    it do
+      expect(sudoku2(x[:grid])).to eql(x[:expected])
+    end
+  end
+end