done USMobile 编译器有问题的oa

自然语言对应到map

https://static.cheggcn.com/chegg/653766.html

https://stackoverflow.com/questions/3422673/how-to-evaluate-a-math-expression-given-in-string-form

不要轻易复制粘贴啊啊啊！

 

变成一位数所需要的次数，加个count就行了

https://www.geeksforgeeks.org/finding-sum-of-digits-of-a-number-until-sum-becomes-single-digit/