2번 문제.

\begin{tikzpicture}[scale=1.5,>=stealth,font=\scriptsize]
\tikzstyle{level 1}=[level distance=10mm,sibling distance=20mm]
\tikzstyle{level 2}=[level distance=10mm,sibling distance=20mm]
\tikzstyle{level 3}=[level distance=7mm,sibling distance=14mm]

\node(0)[solid node]{}
  child[grow=west,level distance=15mm]{node(1){}
    edge from parent [->] node [above] {A}}
  child[grow=south]{node(a)[solid node]{}
       child{node(b)[solid node]{}
       child{edge from parent [->] node [left] {$l$}}
       child{edge from parent [->] node [right] {$r$}}
       edge from parent [->] node [left] {$L$}
  }
  child{node(c)[solid node]{}
    child{edge from parent [->] node [left] {$l$}}
    child{edge from parent [->] node [right] {$r$}}
    edge from parent [->] node [right] {$R$}
  }
  edge from parent [->] node [right] {D}
};
\draw[dashed](b)to(c);

\node [right] at (0) {1};
\node [above left] at (a) {1};
\node [above] at ($(b)!.5!(c)$){2};

\node [left] at (1) {(2,2)};
\node [below] at (b-1) {(4,2)};
\node [below] at (b-2) {(1,1)};
\node [below] at (c-1) {(3,2)};
\node [below] at (c-2) {(0,3)};

\end{tikzpicture}