Compilare: main.cpp: In function 'int bs(std::__cxx11::string, char)': main.cpp:21:9: warning: unused variable 'l' [-Wunused-variable] int l = 0, r = s.length()-1, ans = -1; ^ main.cpp:21:16: warning: unused variable 'r' [-Wunused-variable] int l = 0, r = s.length()-1, ans = -1; ^ main.cpp:21:34: warning: unused variable 'ans' [-Wunused-variable] int l = 0, r = s.length()-1, ans = -1; ^~~ main.cpp:23:1: warning: no return statement in function returning non-void [-Wreturn-type] } ^ main.cpp: In function 'int main()': main.cpp:29:22: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(int r = 0; r < s.length(); r++) { ~~^~~~~~~~~~~~