0) echo "YES" . PHP_EOL; else echo "NO" . PHP_EOL; function run($y,$x,$now){ global $m,$N,$ox,$oy,$memo; if($y==$oy && $x==$ox) $now *= 2; if($now<=0 || $now <= $memo[$y][$x]) return; $memo[$y][$x] = $now; if($y > 0) run($y-1,$x,$now-$m[$y-1][$x]); if($y < $N-1) run($y+1,$x,$now-$m[$y+1][$x]); if($x > 0) run($y,$x-1,$now-$m[$y][$x-1]); if($x < $N-1) run($y,$x+1,$now-$m[$y][$x+1]); } ?>