Hello @WeiZhong thanks for your wonderful work on approach0.xyz! I couldn't be more grateful for it (if you want you can put there a donation button or a https://liberapay.com or https://buymeacoffee.com , i would definitely help a bit if corona doesn't destroy me financially)!
One problem i noticed lately is that it has become harder to find some results, did you change the algorithms lately? I don't have any specific example now but i can look it up if you're interested

Also here's an unrelated problem: there should be a way to search for a specific symbol only, for instance I wanted to …