Solution (source code)

= Solution

The <Gamma function> identity $\Gamma(1/2)=\sqrt\pi$ gives the <Bromwich integral of an inverse square root> directly:
$$
\boxed{I=2i\Gamma(1/2)=2i\sqrt\pi.}
$$
Equivalently, put $x=u^2$ in the real <integral>. It becomes $2\int_0^\infty e^{-u^2}du=\sqrt\pi$ by the <Gaussian integral>.