Compilare: user.cpp: In function ‘void dfs(int)’: user.cpp:15:34: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(int i=0; i<adj[nod].size(); ++i) ^ user.cpp: In function ‘void dfs2(int)’: user.cpp:36:32: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(int i=0; i<q[nod].size(); ++i) ^ user.cpp:42:34: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(int i=0; i<adj[nod].size(); ++i) ^ user.cpp: In function ‘int main()’: user.cpp:53:40: 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:54:42: 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:55:26: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] scanf("%d%d", &n, &m); ^ user.cpp:59:24: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] scanf("%d", &x); ^ user.cpp:62:47: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] for(int i=1;i<=n;++i) scanf("%d", &val[i]); ^ user.cpp:65:34: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] scanf("%d%d",&a[i],&b[i]); ^