Compilare: user.cpp: In function ‘void aux_dfs(int)’: user.cpp:17:29: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for (i=0; i<g[nod].size(); i++){ ^ user.cpp:24:29: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for (i=0; i<g[nod].size(); i++) ^ user.cpp:28:29: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for (i=0; i<g[nod].size(); i++) ^ user.cpp: In function ‘void dfs(int, int)’: user.cpp:39:30: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for (i=0; i<qr[nod].size(); i++){ ^ user.cpp:44:29: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for (i=0; i<g[nod].size(); i++){ ^ user.cpp: In function ‘int main()’: user.cpp:55:38: 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:56:40: 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:57:25: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] scanf("%d %d",&N,&M); ^ user.cpp:61:23: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] scanf("%d",&x); ^ user.cpp:66:26: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] scanf("%d",&v[i]); ^ user.cpp:71:29: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] scanf("%d %d",&x,&y); ^