Compilare: main.cpp: In function 'void topsort()': main.cpp:28:21: warning: comparison of integer expressions of different signedness: 'int' and 'std::vector<int>::size_type' {aka 'long unsigned int'} [-Wsign-compare] 28 | for (int i = 1; i < a[s].size(); i++) | ~~^~~~~~~~~~~~~ main.cpp: In function 'int main()': main.cpp:54:21: warning: comparison of integer expressions of different signedness: 'int' and 'std::vector<int>::size_type' {aka 'long unsigned int'} [-Wsign-compare] 54 | for (int j = 1; j < a[x].size(); j++) | ~~^~~~~~~~~~~~~