function find(array, element)
    local index = 0
    for i = 1, #array do
        if array[i] == element then
            index = i
            break
        end
    end
    return index
end

function showBoard(board)
    for row = 1, 9 do
        print(table.concat(board[row], " "))
    end
end

function cloneBoard(b)
    local c = {}
    for i = 1, 9 do
        c[i] = {}
        for j = 1, 9 do
            c[i][j] = b[i][j]
        end
    end
    return c
end