  Lattice scalar field theories encounter a sign problem when the coupling
constant is complex. This is a close cousin of the real-time sign problems that
afflict the lattice Schwinger-Keldysh formalism, and a more distant relative of
the fermion sign problem that plagues calculations of QCD at finite density. We
demonstrate the methods of complex normalizing flows and contour deformations
on scalar fields in $0+1$ and $1+1$ dimensions, respectively. In both cases,
intractable sign problems are readily bypassed. These methods extend to
negative couplings, where the partition function can be defined only by
analytic continuation. Finally, we examine the location of partition function
zeros, and discuss their relation to the performance of these algorithms.
