\documentclass{article}
\usepackage[T1]{fontenc}
\usepackage{tikz}
\usetikzlibrary{automata}
\usetikzlibrary{positioning}
\usetikzlibrary{fit}
\begin{document}
\tikzset{basic/.style={draw,fill=blue!20,text width=1em}}
\tikzset{functions/.style={basic,circle,fill=blue!10}}
\begin{tikzpicture}[
shorten >=1pt,
node distance=2.5cm,
on grid,
auto
]
\node[state, initial] (q0) {};
\node[state] (q1) [right=of q0] {};
\node[state] (q2) [right=4 of q1] {};
\node[state, accepting] (q3) [right=of q2] {};