latex-pseudocode

Based on package clrscode3e, written by Thomas H. Cormen:

Package for producing pseudocode in the style of Cormen, Leiserson, Rivest, and Stein, Introduction to Algorithms, Third edition.

See more

Example

Documentation

Each pseudocode procedure is typeset within a codebox environment,

    \begin{codebox}...\end{codebox}.

Procedure name

Normally, the first line within the codebox environment is a \Procedure command (optional). The first argument is the procedure name, and the optional second argument is a comma separated list of parameters, each optionally with a description of the parameter (after an equal sign). Example:

    \Procedure{Dijkstra}, \Procedure{Dijkstra}{G, s}, \Procedure{Dijkstra}{G = graph, s = vertex}

Format commands

To typeset a procedure in small caps, use:

    \proc{Insertion-Sort}{Vec} % same as \Procedure

To typeset a constant in small caps, use:

    \const{true}, \const{nil}

To typeset an identifier in italics, use:

    \id{key}, \id{left-sum}

To typeset a fixed function in roman, use:

    \func{sin}{x}, \func{out-degree}{} % same as \Procedure

To typeset a keyword in boldface, use:

    \kw{for}, \kw{if}

To typeset an object attribute with dot syntax, use:

    \member{user}{name}

To typeset an array element with square brackets syntax, use:

    \at{names}{pos}

All these commands not only use the correct font, but they also perform the important service of interpreting a dash as a hyphen, rather than as a minus sign. These commands may be used either in or out of math mode.

To typeset subarray ranges, use:

    $[1 \twodots n]$

Line numbering

Other than the \Procedure line, all lines begin with either \li (for a numbered line) or \zi (for an unnumbered line).

Keywords and indentation

The following commands are provided for typesetting keywords and handling automatic indentation:

• Loops: \For, \To, \By, \Downto, \Do, \While, \Repeat, \Until
• Selection: \If, \Then, \Else, \ElseIf, \ElseNoIf
• Jumps: \Return, \Error, \Goto
• Multithreading: \Spawn, \Sync, \Parfor
• Comments: \Comment, \RComment, \CommentSymbol
• Indentation: \Indentmore, \Startalign, \Stopalign

\label commands appearing in or after the first numbered line in a codebox resolve to the number of the most recent numbered line.

Limitation

This package works only if each procedure has at most 99 numbered lines of code.

Code for the example

\begin{codebox}
    \Procedure{Dijkstra}{G = graph, s = vertex}

    \li \For each vertex $v \in \id{V_G}$
    \li \Do
            $\at{dist}{v} \gets \infty$
    \li     $\at{parent}{v} \gets \const{NIL}$
        \End
    \li $\at{dist}{s} \gets 0$

    \liempty

        $Q \gets \id{V_G}$

    \li \While $Q \neq \emptyset$
    \li \Do
            $u \gets \proc{Extract-Min}{Q}$

    \li     \For each edge $e = (u,v)$
    \li     \Do
                \If $\at{dist}{v} > \at{dist}{u} + \at{weight}{e}$
    \li         \Then
                    $\at{dist}{v} \gets \at{dist}{u} + \at{weight}{e}$
    \li             $\at{parent}{v} \gets u$
                \End
            \End
        \End

    \liempty

        $H \gets (\id{V_G, \emptyset})$
    \li \For each vertex $v \in \id{V_G},\ v \neq s$
    \li \Do
            $\id{E_H} \gets \id{E_H} \cup \{(\at{parent}{v}, v)\}$
        \End

    \liempty

        \Return $H, \id{dist}$
\end{codebox}