Compilare: user.cpp: In function ‘void dfs(int)’: user.cpp:30:42: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for (int i = 0; i < query[node].size(); i++) ^ user.cpp:38:38: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for (int i = 0; i < g[node].size(); i++) ^ user.cpp: In function ‘int main()’: user.cpp:47:40: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] freopen("arbvalmax.in", "r", stdin); ^ user.cpp:48:42: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] freopen("arbvalmax.out", "w", stdout); ^ user.cpp:51:26: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] scanf("%d%d", &n, &m); ^ user.cpp:54:24: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] scanf("%d", &x); ^ user.cpp:59:27: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] scanf("%d", &v[i]); ^ user.cpp:73:30: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] scanf("%d%d", &x, &y); ^