Compilare: user.cpp: In function ‘void PreDFS(int, int)’: user.cpp:20:36: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(int i = 0; i < V[nod].size(); i ++){ ^ user.cpp: In function ‘void DFS(int)’: user.cpp:35:36: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(int i = 0; i < V[nod].size(); i ++){ ^ user.cpp: In function ‘int main()’: user.cpp:53:39: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] freopen("iepuri2.in" ,"r", stdin ); ^ user.cpp:54:39: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] freopen("iepuri2.out","w", stdout); ^ user.cpp:56:27: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] scanf("%d %d", &N, &K); ^ user.cpp:59:31: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] scanf("%d %d", &X, &Y); ^