1236

/**
 * // This is the HtmlParser's API interface.
 * // You should not implement it, or speculate about its implementation
 * class HtmlParser {
 *   public:
 *     vector<string> getUrls(string url);
 * };
 */

class Solution {
public:
    vector<string> crawl(string startUrl, HtmlParser htmlParser) {
        vector<string> ans;
        unordered_set<string> m;
        string hostname = startUrl.substr(0, startUrl.find('/', 7));
        queue<string> q;
        q.push(startUrl);
        m.insert(startUrl);
        ans.push_back(startUrl);
        while(!q.empty()){
            string url = q.front(); q.pop();
            for(auto child: htmlParser.getUrls(url)){
                if(child.find(hostname) == string::npos || m.count(child))
                    continue;
                m.insert(child);
                q.push(child);
                ans.push_back(child);
            }
        }
        return ans;
    }
};