Let us consider an expression tree $($see example below$)$

Select one or more:a$.$ Printing the expression tree, in any of the $3$ notations, is $\backslash (\backslash$mathrm$\{$O$\}\backslash$left$(2^\{\backslash$mathrm$\{$N$\}\}\backslash$right$)\backslash )$ where N is the number of nodesb. Building the expression tree from infirx notation costs $\backslash (\backslash$mathrm$\{$O$\}(\backslash$mathrm$\{$N$\})\backslash )$c$.$ Printing the expression tree, in any of the $3$ notations, is $\backslash ($ O$($N $\backslash$log N$)\backslash )$ where $\backslash ($ N $\backslash )$ is the number of nodesd. Evaluating the expression costs $\backslash (\backslash$mathrm$\{$O$\}(\backslash$mathrm$\{$N$\})\backslash )$e$.$ Printing the expression in postfix form can include brackets