Data commit

Task/Sudoku/PHP/sudoku.php

@@ -0,0 +1,125 @@
+	class SudokuSolver {
+		protected $grid = [];
+		protected $emptySymbol;
+		public static function parseString($str, $emptySymbol = '0')
+		{
+			$grid = str_split($str);
+			foreach($grid as &$v)
+			{
+				if($v == $emptySymbol)
+				{
+					$v = 0;
+				}
+				else
+				{
+					$v = (int)$v;
+				}
+			}
+			return $grid;
+		}
+		
+		public function __construct($str, $emptySymbol = '0') {
+			if(strlen($str) !== 81)
+			{
+				throw new \Exception('Error sudoku');
+			}
+			$this->grid = static::parseString($str, $emptySymbol);
+			$this->emptySymbol = $emptySymbol;
+		}
+		
+		public function solve()
+		{
+			try
+			{
+				$this->placeNumber(0);
+				return false;
+			}
+			catch(\Exception $e)
+			{
+				return true;
+			}
+		}
+		
+		protected function placeNumber($pos)
+		{
+			if($pos == 81)
+			{
+				throw new \Exception('Finish');
+			}
+			if($this->grid[$pos] > 0)
+			{
+				$this->placeNumber($pos+1);
+				return;
+			}
+			for($n = 1; $n <= 9; $n++)
+			{
+				if($this->checkValidity($n, $pos%9, floor($pos/9)))
+				{
+					$this->grid[$pos] = $n;
+					$this->placeNumber($pos+1);
+					$this->grid[$pos] = 0;
+				}
+			}
+		}
+		
+		protected function checkValidity($val, $x, $y)
+		{
+			for($i = 0; $i < 9; $i++)
+			{
+				if(($this->grid[$y*9+$i] == $val) || ($this->grid[$i*9+$x] == $val))
+				{
+					return false;
+				}
+			}
+			$startX = (int) ((int)($x/3)*3);
+			$startY = (int) ((int)($y/3)*3);
+
+			for($i = $startY; $i<$startY+3;$i++)
+			{
+				for($j = $startX; $j<$startX+3;$j++)
+				{
+					if($this->grid[$i*9+$j] == $val)
+					{
+						return false;
+					}
+				}
+			}
+			return true;
+		}
+
+		public function display() {
+			$str = '';
+			for($i = 0; $i<9; $i++)
+			{
+				for($j = 0; $j<9;$j++)
+				{
+					$str .= $this->grid[$i*9+$j];
+					$str .= " ";
+					if($j == 2 || $j == 5)
+					{
+						$str .= "| ";
+					}
+				}
+				$str .= PHP_EOL;
+				if($i == 2 || $i == 5)
+				{
+					$str .=  "------+-------+------".PHP_EOL;
+				}
+			}
+			echo $str;
+		}
+		
+		public function __toString() {
+			foreach ($this->grid as &$item)
+			{
+				if($item == 0)
+				{
+					$item = $this->emptySymbol;
+				}
+			}
+			return implode('', $this->grid);
+		}
+	}
+	$solver = new SudokuSolver('009170000020600001800200000200006053000051009005040080040000700006000320700003900');
+	$solver->solve();
+	$solver->display();