= 0; $i--) { for ($j = 0; $j <= $i; $j++) { $dp[$j] = min($dp[$j], $dp[$j + 1]) + $triangle[$i][$j]; } } return $dp[0]; } public static function minimumTotal2(array $triangle) { if (0 === $n = count($triangle)) { return $n; } $ans = $triangle[$n - 1]; for ($i = $n - 2; $i >= 0; $i--) { for ($j = 0; $j <= $i; $j++) { $ans[$j] = $triangle[$i][$j] + min($ans[$j], $ans[$j + 1]); } } return $ans[0]; } }