books.cpp: In function 'void solve(int, int, long long int, int)':
books.cpp:22:37: warning: comparison of integer expressions of different signedness: 'std::set<int>::size_type' {aka 'long unsigned int'} and 'int' [-Wsign-compare]
22 | for(int i = r; i >= 1 && st.size() <= 2*K; i--){
| ~~~~~~~~~~^~~~~~
books.cpp:32:19: warning: comparison of integer expressions of different signedness: 'int' and 'std::vector<int>::size_type' {aka 'long unsigned int'} [-Wsign-compare]
32 | for(int i = 0;i < all.size(); i++){
| ~~^~~~~~~~~~~~
books.cpp:38:41: warning: comparison of integer expressions of different signedness: 'std::vector<int>::size_type' {aka 'long unsigned int'} and 'int' [-Wsign-compare]
38 | if(sum >= A && sum <= 2*A && v.size() == K){
| ~~~~~~~~~^~~~