[algo footnode] An example shows how to add footnote just below an algorithm. #Latex

algorithm footnote.tex

\documentclass{article}
\usepackage[ruled]{algorithm2e}
\usepackage{amssymb,amsmath,caption}
\usepackage[hang,flushmargin]{footmisc}
\usepackage{lipsum}
\makeatletter
\newcommand{\algorithmfootnote}[2][\footnotesize]{%
  \let\old@algocf@finish\@algocf@finish% Store algorithm finish macro
  \def\@algocf@finish{\old@algocf@finish% Update finish macro to insert "footnote"
    \leavevmode\rlap{\begin{minipage}{\linewidth}
    #1#2
    \end{minipage}}%
  }%
}
\makeatother
\begin{document}
\lipsum[1-3]
\begin{algorithm}[tb]
  \caption{How to write algorithms}\label{algorithm1}
  \algorithmfootnote{$y_0$ denotes the initial value.}
  \KwIn{this text}
  \KwOut{how to write algorithm with \LaTeX2e }
  initialization\;
  \While{not at end of this document}{
    read current\;
    \eIf{understand}{
      go to next section\;
      current section becomes this one\;
      }{
      $y_0 \leftarrow y$\;
    }
  }
\end{algorithm}
\end{document}