Compilare: user.cpp: In function ‘void DFS(int)’: user.cpp:11:19: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(int i=0; i<a[nod].size(); i++){ ^ user.cpp: In function ‘int main()’: user.cpp:40:15: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(i=0; i<sol.size(); i++){ ^ user.cpp:30:39: 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); ^ user.cpp:31:41: 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); ^ user.cpp:33:26: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] scanf("%d%d", &n, &m); ^ user.cpp:35:30: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] scanf("%d%d", &x, &y); ^