Compilare: main.cpp: In function 'int main()': main.cpp:111:11: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] if (r != first_row.size()) { ~~^~~~~~~~~~~~~~~~~~~ main.cpp: In function 'int find_unvisited(std::vector<int>&, std::vector<bool>&)': main.cpp:25:1: warning: control reaches end of non-void function [-Wreturn-type] } ^ main.cpp: In function 'int main()': main.cpp:108:14: warning: 'candidate' may be used uninitialized in this function [-Wmaybe-uninitialized] curr = candidate; ~~~~~^~~~~~~~~~~