Compilare: user.cpp: In function ‘int DFS(int, int)’: user.cpp:21:38: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for (int i = 0; i < g[nod].size (); i++) { ^ user.cpp:27:1: warning: no return statement in function returning non-void [-Wreturn-type] } ^ user.cpp: In function ‘int main()’: user.cpp:73:35: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] freopen ("lca.in", "r", stdin); ^ user.cpp:74:37: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] freopen ("lca.out", "w", stdout); ^ user.cpp:76:27: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] scanf ("%d%d", &N, &Q); ^ user.cpp:80:25: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] scanf ("%d", &X); ^ user.cpp:89:31: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] scanf ("%d%d", &X, &Y); ^