Given a string from the database as follows:

ul[0][id]=main1&ul[0][children][0][id]=child2&ul[0][children][0][class]=&ul[1][id]=main3&ul[2][id]=main4&ul[3][id]=main5

Where what's after the equal sign is an ID, how can I take this string on the backend and build out a list as following from front-end output?

<UL id="container">
    <LI id="main1">

        Lorem ipsum dolor sit amet, consectetur 
        <UL>
            <LI id="child2">

                In hac habitasse platea dictumst. 
                <UL></UL>
            </LI>
        </UL>
    </LI>
    <LI id="main3">

        In hac habitasse platea dictumst. 
        <UL></UL>
    </LI>
    <LI id="main4">

        In hac habitasse platea dictumst. 
        <UL></UL>
    </LI>
    <LI id="main5">

        In hac habitasse platea dictumst. 
        <UL></UL>
    </LI>
</UL>

Thanks