【561】LaTeX 中的算法寫法

參考：Latex-算法偽代碼

參考：帶豎線 algorithm 包（大量代碼可參考）

參考：Latex 建立帶有豎線和編號的算法環境

參考：Latex之使用algorithm2e包來寫算法

---

　　舉例一：

\usepackage[linesnumbered,ruled]{algorithm2e}

\begin{algorithm}[H]
\DontPrintSemicolon
  \SetAlgoLined
  \KwIn {$n \geq 0 \vee x \neq 0$}
  \KwOut {$y = x^n$}
  initialization\;
  $y \gets 1$\;
  \eIf {$n < 0$}{
    $X \gets 1 / x$ \;
    $N \gets -n$ \;
  }{
    $X \gets x$ \;
    $N \gets n$ \;
  }
  
  \While{$N$ is even}{
    \eIf {$n < 0$}{
      $X \gets X \times X$ \;
      $N \gets N / 2$ \;
    }{
      $X \gets x$ \;
      $N \gets n$ \;
    }
  }
  \caption{Calculate $y = x^n$}
\end{algorithm}

　　顯示效果：

\SetKwData{Or}{\textbf{or}}：自定義關鍵字加粗，也可以直接寫

　　舉例二：

\begin{algorithm}
\caption{Improved alpha-shape}
\label{algorithm:alpha_shape}
\SetKwData{In}{\textbf{in}}\SetKwData{To}{to}
\DontPrintSemicolon
\SetAlgoLined
\KwIn {$points, per$}
\KwOut {$concaveHull$}
  \Begin{
  \If{$len(points) < 4$}{
    \Return{$convexHull(points)$}
  }
  
  $triangularMesh \gets DelaunayTriangulation(points)$ \;
  % $edgePoints \gets []$ \;
  % $circumRList \gets []$ \;
  
  \For{$(i_a, i_b, i_c) \in triangularMesh.vertices$}{
    $circumR \gets circumradius(a,b,c)$ \;
    $edgePointsAppend(edgePoints, points[[i_a, i_b,i_c]])$ \;
    $circumRAppend(circumRList, points[[i_a, i_b, i_c]])$ \;
  }
  
  $circumRList \gets sorted(circumRList)$ \;
  $index \gets round(per \times len(circumRList)$ \;
  $threshold \gets circumRList[index]$ \;
  % $deletedEdgePoints \gets []$ \;
  
  \For{$i \gets 0$ \To $len(circumRList)$}{
    \If{$circumRList[i] > threshold$}{
      $deletedEdgePoints.append(edgePoints.pop(i))$ \;
    }
  }
  
  $keptPolys \gets cascaded\_union(edgePoints)$ \;
  $deletedPolys \gets cascaded\_union(deletedEdgePoints)$ \;
  $concaveHull \gets Polygon()$ \;
    \If{$type(deletedPolys) = MultiPolygon$}{
      % $areaPolys \gets []$ \;
      \For{$poly \in deletedPolys$}{
        $areaPolys.append(area(poly))$ \;
      }
      $index_1, area_1 \gets getIndexArea(areaPolys, 1)$ \;
      $index_2, area_2 \gets getIndexArea(areaPolys, 2)$ \;
      \If{$\frac{area_1}{area_2} > 3.0$}{
        $deletedPoly \gets deletedPolys.pop(index_1)$ \;
      }
    }
  $concaveHull \gets keptPolys \cup deletedPolys$ \;
  \Return{$concaveHull$}}
\end{algorithm}

　　顯示效果：

　　舉例三：

\usepackage[ruled,vlined,linesnumbered,ruled]{algorithm2e}

\begin{algorithm}[!ht]
\caption{Alias names Detection}
\label{algorithm:alias_names}
\SetKwData{Or}{\textbf{or}}
\DontPrintSemicolon
%\SetAlgoLined
\KwIn {$polygonDict, p_1, p_2$}
\KwOut {$aliasNames$}
  \Begin{
  % $aliasNames \gets []$\;
  
  \For{$(name_1, poly_1) \in polygonDict.items()$}{
    \For{$(name_2, poly_2) \in polygonDict.items()$}{
      \If{$name_1 \neq name_2$}{
        $poly_1 \gets Polygon(poly_1)$ \;
        $poly_2 \gets Polygon(poly_2)$ \;
        \If{$poly_1 \cap poly_2 \neq \phi$}{
          $polyArea_1 \gets area(poly_1)$ \;
          $polyArea_2 \gets area(poly_2)$ \;
          $intersectArea \gets area(poly_1 \cap poly_2)$ \;
          $unionArea \gets area(poly_1 \cup poly_2)$ \;
          $r_1 \gets \frac{intersectArea}{unionArea}$ \;
          $r_2 \gets \frac{intersectArea}{polyArea_1}$ \;
          $r_3 \gets \frac{intersectArea}{polyArea_2}$ \;
          \If{$r_1 > p_1$ \Or $r_2 > p_2$ \Or $r_3 > p_2$}{
            $aliasNames.append([name_1, name_2])$
          }
        }
      }
    }
  }
  \Return{$aliasNames$}}
\end{algorithm}

　　顯示效果：

　　增加行間距：\vspace{0.3cm}

\begin{algorithm}[!ht]
\caption{Alias names Detection}
\label{algorithm:alias_names}
\SetKwData{Or}{\textbf{or}}
\DontPrintSemicolon
%\SetAlgoLined
\vspace{0.3cm}
\KwIn {$polygonDict, p_1, p_2$}
\KwOut {$aliasNames$}
  \Begin{...}
\end{algorithm}

　　效果顯示：