Tikz graph

\begin{tikzpicture}
\begin{scope}[every node/.style={thick,draw,circle,minimum size=2em,inner sep=1}] % nodos
    \node [label={[green]right:0}] (1) at (3,5){1};
    \node [label={[green]right:$T_1$}](2) at (3,3.5){2};
    \node [label={[green]right:$T_1+T_2$}](3) at (3,2){3};
    \node [label={[green]left:$\sum_{i=1}^3T_i$}](4) at (1.5,0.5){4};
    \node [label={[green]right:$\sum_{i=1}^3T_i$}](5) at (4.5,0.5){5};
    \node [label={[green]left:$\sum_{i=1}^4T_i$}](6) at (0,-1){6};
    \node [label={[green]center:$\sum_{i=1}^3T_i+\max\{T_4,T_5\}$}] (7) at (3,-1){7};

    \node [label={[green]left:$\sum_{i=1}^4T_i+T_6$}](8) at (1.5,-2.5){8};
    \node [label={[green]right:$\sum_{i=1}^3T_i+T_5$}] (9) at (6,-1){9};
    \node [label={[green]center:$\sum_{i=1}^3T_i+\max\Big\{T_4+T_6+T_8,\max\big\{T_4,T_5\big\}+T_7,T_5+T_9\Big\}$}](10) at (4.5,-3.5){10};
\end{scope}
\begin{scope}[every edge/.style={draw,thick}] % arcos
\draw[->] (1) edge node[left] {$T_1$} (2);
\draw[->] (2) edge node[left] {$T_2$} (3);
\draw[->] (3) edge node[left] {$T_3$} (4);
\draw[->] (3) edge node[right] {$T_3$} (5);
\draw[->] (4) edge node[left] {$T_4$} (6);
\draw[->] (4) edge node[right] {$T_4$} (7);
\draw[->] (5) edge node[left] {$T_5$} (7);
\draw[->] (5) edge node[right] {$T_5$} (9);
\draw[->] (6) edge node[left] {$T_6$} (8);
\draw[->] (7) edge node[left] {$T_7$}(10);
\draw[->] (8) edge node[below] {$T_8$} (10);
\draw[->] (9) edge node[right] {$T_9$} (10);
\end{scope}
\end{tikzpicture}