foo.cc: In function 'LL findmax(std::vector<long long int>&, LL)':
foo.cc:34:33: warning: suggest parentheses around '+' inside '>>' [-Wparentheses]
   34 |                 int mid = l + r + 1 >> 1;
      |                           ~~~~~~^~~
foo.cc: In function 'int main()':
foo.cc:56:23: warning: comparison of integer expressions of different signedness: 'int' and 'std::vector<long long int>::size_type' {aka 'long unsigned int'} [-Wsign-compare]
   56 |         for(int i=0; i<b.size(); i++)
      |                      ~^~~~~~~~~

[Hydro](https://hydro.ac)提供评测服务