books.cpp: In function 'long long int minimum_walk(std::vector<int>, int)':
books.cpp:16:30: warning: comparison of integer expressions of different signedness: '__gnu_cxx::__alloc_traits<std::allocator<int>, int>::value_type' {aka 'int'} and 'std::vector<int>::size_type' {aka 'long unsigned int'} [-Wsign-compare]
16 | while(p.size() && p.back()+1==p.size())
| ~~~~~~~~~~^~~~~~~~~~
books.cpp:27:15: warning: comparison of integer expressions of different signedness: 'int' and 'std::vector<int>::size_type' {aka 'long unsigned int'} [-Wsign-compare]
27 | for(int i=0;i<p.size();i++)
| ~^~~~~~~~~
books.cpp:38:9: warning: comparison of integer expressions of different signedness: 'int' and 'std::vector<int>::size_type' {aka 'long unsigned int'} [-Wsign-compare]
38 | if(i+1!=p.size() && mex>i)
| ~~~^~~~~~~~~~