foo.cc: In function 'void solve(char*, char*)':
foo.cc:8:15: warning: comparison between signed and unsigned integer expressions [-Wsign-compare]
  for(int i=0;i<strlen(s)-1;i++){
              ~^~~~~~~~~~~~
foo.cc: In function 'int main()':
foo.cc:30:10: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result]
     scanf("%s",s);           //s为要处理的加密字符串，答案储存在ans里
     ~~~~~^~~~~~~~

[Hydro](https://hydro.ac)提供评测服务