Baidu does support both regular sitemap.xml files as well as sitemap index files (multiple sitemaps divided up) it also supports a ping address should you wish to make use of that
http://ping.baidu.com/ping/RPC2
The best way forward, at least in my opinion for most every search engine is to add your sitemap to the/a robots.txt file
Sitemap: <url to your sitemap>
see googles documentation on this here I would have provided a page from Baidu but sadly I don't read the language and the English documentation mostly relates blocking Baidu.