Compilare: main.cpp: In function 'void dfs(std::vector<std::vector<int> >&, std::vector<int>&, std::vector<int>&, int)': main.cpp:13:16: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(int i=0; i<arcs[currentNode].size(); ++i) { ~^~~~~~~~~~~~~~~~~~~~~~~~~ main.cpp: In function 'int main()': main.cpp:46:16: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(int i=0; i<finalOrder.size(); ++i) ~^~~~~~~~~~~~~~~~~~ main.cpp:25:36: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)', declared with attribute warn_unused_result [-Wunused-result] freopen("sortaret.in", "r", stdin); ^ main.cpp:26:39: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)', declared with attribute warn_unused_result [-Wunused-result] freopen("sortaret.out" , "w", stdout); ^ main.cpp:30:23: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result] scanf("%d%d", &n, &m); ^ main.cpp:37:24: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result] scanf("%d%d", &x, &y); ^