Compilare: user.cpp: In function ‘int DFS(int)’: user.cpp:17:42: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for (int i = 0; i < graph[node].size(); i++) { ^ user.cpp:23:1: warning: no return statement in function returning non-void [-Wreturn-type] } ^ user.cpp: In function ‘int df(int)’: user.cpp:27:43: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for (int i = 0; i < revers[node].size(); i++) { ^ user.cpp:33:1: warning: no return statement in function returning non-void [-Wreturn-type] } ^ user.cpp: In function ‘int solve()’: user.cpp:56:41: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for (int j = 0; j < sol[i].size(); j++) { ^ user.cpp:61:1: warning: no return statement in function returning non-void [-Wreturn-type] } ^ user.cpp: In function ‘int main()’: user.cpp:65:34: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] freopen("ctc.in", "r", stdin); ^ user.cpp:66:36: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] freopen("ctc.out", "w", stdout); ^ user.cpp:68:27: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] scanf("%d %d", &n, &m); ^ user.cpp:70:31: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] scanf("%d %d", &x, &y); ^