N-Queens — backtracking

    \begin{algorithm}
    \caption{SolveNQueens}
    \begin{algorithmic}
    \FUNCTION{SolveNQueens}{row}
        \IF{$row = n$}
            \RETURN true
        \ENDIF
        \FOR{$col \gets 0$ \TO $n - 1$}
            \IF{IsSafe(row, col)}
                \STATE $queen[row] \gets col$
                \IF{SolveNQueens(row + 1)}
                    \RETURN true
                \ENDIF
                \STATE $queen[row] \gets empty$
            \ENDIF
        \ENDFOR
        \RETURN false
    \ENDFUNCTION
    \end{algorithmic}
    \end{algorithm}