I had an exam on *Theory of Computation*, and one of the questions was to write down a regular expression for the language over $\{0,1\}$ consisting of all words containing at least one 1. My answer was:

$$ 0^* 1 0^* (0^* 1 0^*)^* \, . $$

My teacher gave me one mark out of 5, yet I can't find a possible string that will give false output here! His answer, which was $(0+1)^*1(0+1)^*$, was better, but mine works as well, I believe.

> Is my answer correct?