  The graph exploration problem is to visit all the nodes of a connected graph
by a mobile entity, e.g., a robot. The robot has no a priori knowledge of the
topology of the graph or of its size. Cohen et al. \cite{Ilcinkas08} introduced
label guided graph exploration which allows the system designer to add short
labels to the graph nodes in a preprocessing stage; these labels can guide the
robot in the exploration of the graph. In this paper, we address the problem of
adjustable 1-bit label guided graph exploration. We focus on the labeling
schemes that not only enable a robot to explore the graph but also allow the
system designer to adjust the ratio of the number of different labels. This
flexibility is necessary when maintaining different labels may have different
costs or when the ratio is pre-specified. We present 1-bit labeling (two
colors, namely black and white) schemes for this problem along with a labeling
algorithm for generating the required labels. Given an $n$-node graph and a
rational number $\rho$, we can design a 1-bit labeling scheme such that
$n/b\geq \rho$ where $b$ is the number of nodes labeled black. The robot uses
$O(\rho\log\Delta)$ bits of memory for exploring all graphs of maximum degree
$\Delta$. The exploration is completed in time
$O(n\Delta^{\frac{16\rho+7}{3}}/\rho+\Delta^{\frac{40\rho+10}{3}})$. Moreover,
our labeling scheme can work on graphs containing loops and multiple edges,
while that of Cohen et al. focuses on simple graphs.
