Compilare: user.cpp: In function ‘void dfs(int)’: user.cpp:21:38: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for (int i = 1; i<=a[nod].size()-1; ++i) { ^ user.cpp: In function ‘void dfst(int)’: user.cpp:35:39: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for (int i = 1; i<=b[nod].size() -1; ++i) { ^ user.cpp: In function ‘int main()’: user.cpp:45:38: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] freopen ("retele.in", "r", stdin); ^ user.cpp:46:40: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] freopen ("retele.out" ,"w", stdout); ^ user.cpp:48:27: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] scanf ("%d%d", &n, &m); ^ user.cpp:56:32: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] scanf ("%d%d" , &x, &y); ^