Compilare: main.cpp: In function 'int mex(const std::vector<int>&)': main.cpp:16:16: warning: comparison of integer expressions of different signedness: 'int' and 'std::vector<int>::size_type' {aka 'long unsigned int'} [-Wsign-compare] 16 | if(val < used.size()) | ~~~~^~~~~~~~~~~~~ main.cpp:18:22: warning: comparison of integer expressions of different signedness: 'int' and 'std::vector<int>::size_type' {aka 'long unsigned int'} [-Wsign-compare] 18 | for(int i = 0; i < used.size(); i++) | ~~^~~~~~~~~~~~~ main.cpp:14:40: warning: control reaches end of non-void function [-Wreturn-type] 14 | vector <int> used(values.size() + 1); | ^