Compilare: main.cpp: In function 'void dfs_time(int)': main.cpp:26:22: warning: comparison of integer expressions of different signedness: 'int' and 'std::vector<int>::size_type' {aka 'long unsigned int'} [-Wsign-compare] 26 | for(i = 0; i < a[x].size(); ++i) | ~~^~~~~~~~~~~~~ main.cpp: In function 'void dfs(int)': main.cpp:91:22: warning: comparison of integer expressions of different signedness: 'int' and 'std::vector<int>::size_type' {aka 'long unsigned int'} [-Wsign-compare] 91 | for(i = 0; i < a[x].size(); ++i) | ~~^~~~~~~~~~~~~