20/20，第一次没调试就过了。

#include
    
     using namespace std;/*1.standardize2.put to the sets3.minus*/set
     
       charset;vector
      
        broken;int main(){    string strA,strB;    cin>>strA>>strB;    transform(strA.begin(),strA.end(),strA.begin(),::toupper);    transform(strB.begin(),strB.end(),strB.begin(),::toupper);    for(int i=0;i