%------------------------------------------------------------------------------------------------------------
%%%  基于树的解码方法 - chart-based decoding
\begin{center}
\begin{tikzpicture}\footnotesize
\begin{scope}[scale=0.7]
\node [anchor=center,draw,thick,circle,inner sep=13pt,ublue] (s1) at (0,0) {};
\node [anchor=north] (t11) at ([yshift=-0.8em]s1.north) {VP};
\node [anchor=north] (t12) at ([yshift=-0.3em]t11.south) {[0,2]};

\node [anchor=center,draw,thick,circle,inner sep=13pt,ublue] (s2) at ([xshift=12em,yshift=-5em]s1.north) {};
\node [anchor=north] (t21) at ([yshift=-0.8em]s2.north) {NP};
\node [anchor=north] (t22) at ([yshift=-0.3em]t21.south) {[0,2]};

\node [anchor=center,draw,thick,circle,inner sep=13pt,ublue] (s3) at ([xshift=-6em,yshift=-13em]s1.south) {};
\node [anchor=north] (t31) at ([yshift=-0.8em]s3.north) {VV};
\node [anchor=north] (t32) at ([yshift=-0.3em]t31.south) {[0,1]};

\node [anchor=center,draw,thick,circle,inner sep=13pt,ublue] (s4) at ([xshift=13em,yshift=2.9em]s3.south) {};
\node [anchor=north] (t41) at ([yshift=-0.8em]s4.north) {NN};
\node [anchor=north] (t42) at ([yshift=-0.3em]t41.south) {[1,2]};

\node [anchor=center,draw,thick,circle,inner sep=13pt,ublue] (s5) at ([xshift=13em,yshift=2.9em]s4.south) {};
\node [anchor=north] (t51) at ([yshift=-0.8em]s5.north) {NP};
\node [anchor=north] (t52) at ([yshift=-0.3em]t51.south) {[1,2]};

{
\draw [->,red!50,very thick] ([xshift=-1em,yshift=-0.3em]s3.north) .. controls +(north:10em) and +(south:10em) .. ([xshift=0em,yshift=0em]s1.south);
\draw [->,red!50,very thick] ([xshift=-1em,yshift=-0.3em]s5.north) .. controls +(north:8em) and +(south:14em) .. ([xshift=0em,yshift=0em]s1.south);
}

{
\draw [->,blue!50,very thick] ([xshift=-1em,yshift=-0.3em]s4.north) .. controls +(north:8em) and +(south:8em) .. ([xshift=0em,yshift=0em]s2.south);
\draw [->,blue!50,very thick] ([xshift=1em,yshift=-0.3em]s5.north) .. controls +(north:9em) and +(south:7em) .. ([xshift=0em,yshift=0em]s2.south);
}

\node [anchor=north] (t51) at ([yshift=7em]s3.north) {edge1};
\node [anchor=north] (t52) at ([xshift=-2em,yshift=7.5em]s5.north) {edge2};
\end{scope}
\end{tikzpicture}
\end{center}